Millionaire’s Shortbread
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With a buttery shortbread base, gooey caramel center, and rich chocolate topping, millionaire’s shortbread bars are every bit as decadent as their name suggests.
Known as millionaire’s shortbread, presumably because they’re so rich, these bars start with a buttery shortbread base, followed by a layer of gooey caramel, and are finished with a chocolate topping sprinkled with flaky sea salt. To me, they taste like gourmet Twix bars, but even more indulgent. While the recipe is straightforward, you will need an instant-read thermometer to cook the caramel to just the right consistency—it’s worth the precision for that perfectly gooey texture.
“OH MY. Decadent!!! Everyone LOVED it.”
What You’ll Need To Make Millionaire’s Shortbread
- All-Purpose Flour: Forms the base of the shortbread crust.
- Dark Brown Sugar: Adds sweetness and a hint of molasses flavor to the crust and caramel.
- Cornstarch: Helps make the shortbread crust tender.
- Butter: Creates the flaky, crumbly texture of the crust and enriches the caramel.
- Egg Yolk: Binds the shortbread dough and contributes richness.
- Sweetened Condensed Milk: Forms the base of the caramel, lending creaminess and sweetness.
- Heavy Cream: Adds richness and smoothness to the caramel layer.
- Light Corn Syrup: Prevents the caramel from crystallizing, ensuring a smooth consistency.
- Vanilla Extract: Enhances the flavor of the caramel with warm, sweet notes.
- Semi-Sweet Chocolate & Milk Chocolate: A combination that balances bitterness and sweetness for the smooth, glossy topping. Use a high-quality brand, such as Ghirardelli.
- Flaky Sea Salt: Adds a touch of crunch and balances the sweetness of the bars.
- Jump to the printable recipe for precise measurements
Step-by-Step Instructions
Make the crust: Preheat the oven to 350°F. Line a 9-inch square pan with aluminum foil, and grease with nonstick cooking spray or butter. In the bowl of a food processor fitted, combine the flour, brown sugar, cornstarch, and salt; process until well combined. Add the butter and egg yolk; process until a coarse meal forms.
Add the ice water and blend until you have a moist, crumbly dough, about 10 seconds more.
Dump the dough into the prepared pan and press with your fingers into an even layer. Prick the dough all over with a fork and bake until golden, about 20 minutes.
Make the caramel layer: In a medium, heavy-bottomed saucepan over medium heat, melt the butter. Add the sweetened condensed milk, heavy cream, corn syrup, vanilla, brown sugar, and salt, whisking until evenly combined. Bring to a simmer and continue cooking, stirring frequently, until the mixture registers between 236°F and 239°F on an instant-read digital thermometer.
Once the caramel reaches the desired temperature, carefully pour it over the crust. Let sit for 30 to 35 minutes, until set but still slightly warm.
Make the chocolate layer: Place the semi-sweet and milk chocolate in a small microwave-safe bowl. Microwave in bursts, stirring in between, until the chocolate is melted and smooth.
Using an offset spatula, spread the chocolate evenly over the caramel layer.
Refrigerate until the bars are cold and the chocolate is set, 1½ to 2 hours. Let the bars sit out for 10 to 15 minutes to soften the chocolate slightly, then cut into small squares and sprinkle with flaky sea salt.
The bars can be prepared up to 3 days in advance and stored in an airtight container in the refrigerator.
Video Tutorial
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Millionaire's Shortbread
With a buttery shortbread base, gooey caramel center, and rich chocolate topping, millionaire’s shortbread bars are every bit as decadent as their name suggests.
Ingredients
For the Crust
- 1 cup all-purpose flour, spooned into measuring cup and leveled-off
- ¼ cup dark brown sugar
- 2 teaspoons cornstarch
- ½ teaspoon salt
- 1 stick (½ cup) cold unsalted butter, cut into ½-inch cubes
- 1 large egg yolk
- 1 tablespoon ice water
For the Caramel Layer
- 1 stick (½ cup) unsalted butter
- 1 (14-ounce) can sweetened condensed milk
- ½ cup heavy cream
- ½ cup light corn syrup
- 1 teaspoon vanilla extract
- 1 cup (packed) dark brown sugar
- ½ teaspoon salt
For the Chocolate Layer
- 3 ounces semi-sweet chocolate, chopped
- 3 ounces milk chocolate, chopped
- Flaky sea salt, for serving
Instructions
For the Crust
- Preheat the oven to 350°F and set an oven rack in the middle position. Line a 9-inch square pan with aluminum foil, pushing the foil neatly into the corners and up the sides of the pan, using two pieces if necessary to ensure that the foil overlaps all edges (the overhang will help removal from the pan). Spray the foil with nonstick cooking spray or grease with butter.
- In the bowl of a food processor fitted with a metal blade, combine the flour, brown sugar, cornstarch, and salt; process until well combined and no lumps of sugar remain. Add the butter and egg yolk; process for 10 to 15 seconds, until a coarse meal forms. Add the ice water and blend until you have a moist, crumbly dough, about 10 seconds more. Dump the dough into the prepared pan and press with your fingers into an even layer (dust your fingers with flour if the dough is too sticky). Prick the dough all over with a fork and bake until golden, about 20 minutes. Set aside to cool.
For Caramel Layer
- In a medium, heavy-bottomed saucepan over medium heat, melt the butter. Add the sweetened condensed milk, heavy cream, corn syrup, vanilla, brown sugar, and salt, whisking until evenly combined. Bring to a simmer and continue cooking, stirring frequently, until the mixture registers between 236°F and 239°F on an instant-read digital thermometer, 10 to 20 minutes. (Note: It's important to use an instant-read thermometer, rather than a clip-on candy thermometer, as temperatures can vary in different spots of the caramel. An instant-read thermometer allows you to test the temperature in multiple areas for accuracy; aim for an average if the readings differ.) Once the caramel reaches the desired temperature, carefully pour it over the crust—remember, it’s extremely hot. Tilt the pan to spread the caramel evenly. Let sit for 30 to 35 minutes, until the caramel layer is set but still slightly warm. (See note below on cleaning the pot.)
For Chocolate Layer
- Place the semi-sweet and milk chocolate in a small microwave-safe bowl. Microwave in 20-second bursts, stirring in between, until the chocolate is about 75% melted. Continue melting in 5 to 10 second-bursts, stirring in between until the chocolate is melted and smooth. Do not overheat or the mixture will break.
- Using an offset spatula, spread the chocolate evenly over the caramel layer. Refrigerate until the bars are cold and the chocolate is set, 1½ to 2 hours. Let the bars sit out for 10 to 15 minutes to soften the chocolate slightly. Lift the bars out of the pan using the foil overhang and transfer to a cutting board. Using a sharp knife, cut into small squares (if the chocolate seems brittle, let the bars sit at room temperature a bit longer before cutting). Sprinkle the bars with flaky sea salt. Store in the refrigerator; serve cold or slightly chilled.
- Make-Ahead Instructions: These bars can be prepared up to 3 days in advance and stored in an airtight container in the refrigerator. Freezing is not recommended, as it may cause the chocolate to bloom.
- Tip for cleaning the caramel pot: To easily clean any caramel residue, fill the pot with water and bring it to a boil. The hot water will loosen the stuck-on caramel, making it much easier to clean.
Nutrition Information
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- Per serving (25 servings)
- Calories: 174
- Fat: 9 g
- Saturated fat: 5 g
- Carbohydrates: 23 g
- Sugar: 17 g
- Fiber: 1 g
- Protein: 2 g
- Sodium: 54 mg
- Cholesterol: 27 mg
This website is written and produced for informational purposes only. I am not a certified nutritionist and the nutritional data on this site has not been evaluated or approved by a nutritionist or the Food and Drug Administration. Nutritional information is offered as a courtesy and should not be construed as a guarantee. The data is calculated through an online nutritional calculator, Edamam.com. Although I do my best to provide accurate nutritional information, these figures should be considered estimates only. Varying factors such as product types or brands purchased, natural fluctuations in fresh produce, and the way ingredients are processed change the effective nutritional information in any given recipe. Furthermore, different online calculators provide different results depending on their own nutrition fact sources and algorithms. To obtain the most accurate nutritional information in a given recipe, you should calculate the nutritional information with the actual ingredients used in your recipe, using your preferred nutrition calculator.
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Hi A.B. I had a similar problem with coffee caramels I make over the holidays. It turned out that elevation makes a difference when making candy. I live at 2600 feet and the rule of of thumb is reduce the temperature listed by 1 degree for every 500 feet above sea level. So on my recipes I reduce the temperature by 5 degrees on the candy thermometer and the results are perfect. Just what I am looking for. Hope this helps.
Hi Jenn!!
I love all your recipes, you are always my go to! I am wondering if there is a way to may these in a 13x9in pan? With my large family, these would not last long at our house:)
Thank you!
Hi, for the best results, I’d use two 9-inch pans. Hope everyone enjoys!
Any advice on how to cut these? I made them last year and the Carmel oozed out and the chocolate layer cracked. I tried using a knife warmed in hot water, freezing, for a bit, and neither made much of a difference. Thank!
Hi Mama K, I wouldn’t freeze them as that’s why the chocolate cracked. Just make sure you slice them immediately after removing them from the fridge when the caramel is solid. (And I always use a sharp chef’s knife to cut these.) Hope that helps!
Hi Jenn
I made these last year and they were a hit. I want to use the caramel in this recipe to make turtles but I noticed that you say to refrigerate. Why is that? If I use this caramel for chocolates would they need to be refrigerated? Not enough corn syrup to be shelf stable? Thanks so much in advance for any advice! I want to start a small in home chocolate business so I am trying to make sure my product doesn’t go bad at room temp.
Hi Jennifer, I’m not 100 percent sure they’d be shelf-stable, so to be safe, I wouldn’t recommend it. Sorry (but good luck with your business)! 🙂
This was another bar cookie I made for the first time this past Christmas to give to friends. It was a very popular addition. So delicious and easy to make.
I always make millionaire shortbread at Christmas and I was looking for a new recipe of it and stumbled upon this one. I was a little intimidated making the caramel but it was so delicious and a nice thick layer. Loved it! As did those I gifted them too!
Just asking out of curiosity: most shortbread recipes I’ve seen don’t call for brown sugar or egg yolk, right? I was wondering if you had any guesses as to why this one is so different? No complaints – it’s delicious! I was just wondering about the difference between this crust and a classic shortbread with just butter, powdered sugar, flour, vanilla and salt.
Hi Kelly, The brown sugar and egg yolk just add more flavor and richness. Hope that clarifies!
I have been making traditional Scottish shortbread for many years, based on a newspaper article on variations of shortbread. It does indeed call for brown sugar and an egg and is baked in a pan and cut into bars (or wedges). Typical American shortbread seems to be made with icing sugar and no egg, and is baked as cookies on a sheet. The base of Millionaire’s Shortbread is Scottish shortbread.
I have also been making a version of Millionaire’s Shortbread since the 1990’s, found in a Safeway Christmas recipe flyer. It was called Chocolate Caramel Squares and is very similar to this one, but with a shallower caramel layer. Always a family favourite!
Oops! They were called Caramel Toffee Squares, and the base didn’t include an egg.
Had to use what I had in the pantry and they still turned out great!! I had pecan sandies purchased for another recipe but I couldn’t remember that recipe (how many others do this?). Finely processed in the food processor meant that I didn’t think they needed any more butter so pressed into 9” pan and heated in 300 oven 5 minutes. I also didn’t have dark corn syrup or brown sugar but that was no issue. No candy thermometer here so used my (clean) meat thermometer. So yummy!! Could this caramel recipe be used to make soft individually-wrapped caramels? Next time it’s likely I won’t have the cookies on hand but think I will add finely chopped pecans to the shortbread recipe.
So glad you enjoyed these! Yes I do think it would work.
This is a delicious recipe but my caramel was a bit stickier than I would have liked. How can I alter the ingredients to make it thicker or is to more to do with the temperature?
Hi Jenn, I am a HUGE fan of your recipes and have successfully made most of them gluten free and all just delicious! I am wanting to make these millionaire bars for a Christmas gathering and have a niece with egg allergies. So, my question is would the crust used for your lemon bars work for this? Or is there an egg substitute you can recommend?
Sure, Adria, that should work (and so glad you’re a fan of the recipes 💓). Hope you enjoy!
Thanks so much for your response! I cannot tell you how many times I’ve said to my dinner guests “This dinner was brought to you by Jenn from Once Upon a Chef!”. So, really, thank you for sharing your talents with us! Enjoy your holidays!
❤️