Millionaire’s Shortbread
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With a buttery shortbread base, a thick layer of gooey caramel, and a chocolate topping, millionaire’s shortbread is as indulgent as it sounds. Think of it as a homemade Twix bar—only richer and even more satisfying.
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’ll need an instant-read thermometer to cook the caramel to just the right consistency—it’s worth it for that perfectly gooey texture.
If you love layered dessert bars, you might also enjoy my pecan pie bars, chocolate peanut butter squares, or raspberry jam bars—same idea, different flavors.
“OH MY. Decadent!!! Everyone LOVED it.”
What You’ll Need To Make Millionaire’s Shortbread
- All-Purpose Flour & Cornstarch: Form the base of the shortbread crust. The cornstarch makes the crust more tender.
- Dark Brown Sugar: Adds sweetness and a hint of molasses flavor to the crust and caramel.
- 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 & Heavy Cream: Form the creamy, sweet base of the caramel.
- 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
Step 1: Mix the dry ingredients. In the bowl of a food processor fitted with the steel blade, combine the flour, brown sugar, cornstarch, and salt, and process until well combined. Add the butter and egg yolk and process until a coarse meal forms.
Step 2: Incorporate the water. Add the ice water and blend until you have a moist, crumbly dough, about 10 seconds more.
Step 3: Press and bake the crust. 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 in a 350°F oven until golden, about 20 minutes.
Pro Tip: Pricking the dough all over with a fork allows steam to escape, preventing the shortbread from bubbling up and creating an uneven surface for your caramel layer.
Step 4: 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 cook, stirring frequently, until the mixture registers between 236°F and 239°F on an instant-read digital thermometer.
Pro Tip: Make sure to scrape the corners of the pot while the caramel cooks, as the milk solids in the condensed milk can scorch quickly on the bottom.
Step 5: Set the caramel. Once the caramel reaches the desired temperature, carefully pour it over the crust. Let it sit for 30 to 35 minutes until set but still slightly warm.
Pro Tip: Don’t rush here—ensure the caramel has cooled to a lukewarm temperature before adding the chocolate; if the caramel is too hot, it will melt into the chocolate rather than stay a distinct layer.
Step 6: Melt the chocolate. 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.
Step 7: Spread the chocolate. Using an offset spatula, spread the melted chocolate evenly over the caramel layer.
Step 8: Chill, slice, and serve. 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 slightly, then cut into small squares and sprinkle with flaky sea salt.
Pro Tip: For perfectly clean edges, run a sharp chef’s knife under hot water and wipe it dry between every single cut; the heat will glide through the chilled chocolate and caramel without sticking.
The bars can be prepared up to 3 days in advance and stored in an airtight container in the fridge.
Video Tutorial
More Decadent Treats & Homemade Candy
Millionaire's Shortbread
Ingredients
For the Crust
- 1 cup all-purpose flour, spooned into measuring cup and leveled-off
- ¼ cup (packed) dark brown sugar
- 2 teaspoons cornstarch
- ½ teaspoon salt
- ½ cup (1 stick) cold unsalted butter, cut into ½-in (13-cm) cubes
- 1 large egg yolk
- 1 tablespoon ice water
For the Caramel Layer
- ½ cup (1 stick) unsalted butter
- 1 (14-oz) 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 oz semi-sweet chocolate, best quality such as Ghiradelli, chopped
- 3 oz milk chocolate, chopped
- Flaky sea salt, for serving
Instructions
For the Crust
- Preheat the oven to 350°F (175°C) and set an oven rack in the middle position. Line a 9-in (23-cm) 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° and 239°F (113° and 115°C) 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.
Notes
- 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.
- 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.
Nutrition Information
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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Hello! I can’t say I’ve made the recipe (I’m sure it is wonderful) but just want to let you know that the squares actually originated in Australia in the 1970’s. They did pick up the now common name “Millionaire’s Shortbread” in Scotland, though.
TM, I came here to make the same comment. We lived in London, where Millionaire Bars were ubiquitous. These are so rich, I think we should call them Billionaire Bars!
Have you ever tried scaling this up to a half sheet pan?
I haven’t, Megan. Please LMK how it turns out if you try it!
I have made this recipe several times. My family loves it!
Followed the recipe to a t and it came out just like the photos. Flavors were good and not too sweet. It’s caramel, people! Super easy and great to make ahead and keep in fridge. Thanks, Jenn!
Amazing! I had to make these twice in a month because they are so good. Really important to get the caramel temperature correct, had a gooey layer one time, which was just as delicious, but of course messy.
Jenn : How can I incorporate desicated coconut, cocoa powder and walnuts into the base? I would like to try it as a base for nanaimo bars. Appreciate your suggestions, thank you very much!
Hi Bob, I think you could get away with replacing 1 to 2 tablespoons of the flour with cocoa powder. Additionally, you can add a quarter cup each of the coconut and the walnuts to the crust batter. Make sure that you really finely chop the walnuts in order to get them to incorporate with the remainder of the crust. Please keep in mind that I’ve never made additions to the crust like this, so I can’t guarantee the results. 🙂 I’d love to hear how it turns out if you try them this way!
These were fantastic!
I think that some of the sugar could be cut from the caramel. The result is sickeningly sweet.
I made these since I love caramel!! Very easy to make and I have no real experience using a candy thermometer….no problem cutting into squares either….will definitely make these again!! YUM!
I’m snowed in (housebound), in Western NC, and would love to make this recipe, but I don’t have corn syrup. I just read I can make my own corn syrup with 1 1/4 cups of sugar dissolved in 1/4 of water. Do you think this would work? If not, is there anything else I can use to substitute for the corn syrup.
Thank you!
Jennifer
I heard about the snowstorm you got in NC – hope all is well and things are starting to get back to normal! I don’t think that the sugar/water mixture you described would work as a replacement for corn syrup – sorry! There are other ways of making the caramel layer, such as melting down caramel squares with some heavy cream. In a small saucepan, melt 2 cups caramel squares with 3 tablespoons cream over low heat. Pour the caramel over the cooled crust and set in the refrigerator for 30 minutes to chill and firm up. (If you don’t have corn syrup at home, you may not have caramel squares and/or heavy cream, so not certain it solves your problem…) 🙂
I made my own using this recipe. Very time consuming, I had to cook it almost an hour, not 45 min. as described, but it worked perfectly. I cut the recipe in 1/2, which meant I did not do the first step as long as described or the sugar would have crystallized.
Hi, If you are keeping them for eating now, would you store them in an air tight container at room temperature or in the fridge?
They should be stored in the fridge – enjoy!
I made these for my husbands work Christmas Party. I had carefully read the reviews and was a little concerned about how my caramel layer would turn out. I bake almost everyday, but very rarely use a thermometer. I am excited to share that it turned out perfectly. These treats are also a great addition to a buffet of sweet bites. They are not only delicious, but also very attractive on a platter! Thanks for another wonderful recipe.