For the Cake

1. Position a rack in the center of the oven and heat the oven to 350°F. Spray two 9-inch cake pans (or a 9x13-inch cake pan) with nonstick cooking spray with flour, like Baker’s Joy or Pam with Flour. Line the bottom of each pan with parchment paper; lightly spray the paper with nonstick spray with flour.
2. In a small bowl, soak the currants in ½ cup hot tap water for 15 minutes. Drain and set aside.
3. In a medium bowl, whisk together the flour, baking soda, salt, cinnamon, nutmeg, allspice, and cloves. Transfer ¼ cup of this mixture to a small bowl and add the drained currants and chopped nuts; toss to combine.
4. In a large bowl, whisk the eggs, granulated sugar, and brown sugar until blended. Add the oil and whisk until evenly combined. Add the flour mixture, carrots, and the currant-nut mixture, and stir with a rubber spatula until evenly incorporated.
5. Scrape the batter evenly into the prepared pans. Bake until a toothpick inserted in the center of the cakes comes out clean, about 40 minutes for 9-inch layers or 45 minutes for a 9x13-inch sheet cake. Let cool in the pans on a rack for about 30 minutes, then invert the cakes onto the rack, remove the parchment paper, and cool completely.

For the Frosting

1. In the bowl of an electric mixer fitted with the paddle attachment or beaters, combine the cream cheese, butter, vanilla and salt. Mix on low speed until combined, then increase the speed to medium-high and beat until aerated and light, about 2 minutes. Gradually add the confectioners' sugar, mixing on low to combine. Once all of the sugar is mixed in, increase the speed to medium-high and beat until fluffy, about 1 minute.
2. After the cake layers have completely cooled, assemble and frost the cake. Decorate the edges with the nuts, if using. The cake keeps nicely for up to 3 days when stored under a cake dome in the refrigerator. Bring to room temperature before serving.
3. Note: To shred the carrots, simply use the small holes on your handheld or box grater. If you prefer, you can also roughly chop the carrots, place them into a food processor fitted with the steel blade, and pulse them until they're very finely chopped, about the consistency of couscous.
4. Note: This recipe provides just enough frosting to ice a 9-inch layer cake (or to generously frost a 9x13-inch sheet cake). For an extra generous layer of frosting on a layer cake, consider leaving the sides bare—it's pretty that way—or boost the frosting amount by 25% for fuller coverage. (The adjusted quantities would be: 10 oz of cream cheese, 10 tablespoons of butter, 1¼ teaspoons of vanilla extract, a generous pinch of salt, and 5 cups of confectioners' sugar.)
5. Freezer-Friendly Instructions: The cake layers can be frozen for up to 3 months. To freeze, wrap the unfrosted cake layers individually in plastic wrap and then in aluminum foil to prevent freezer burn. They can be stored in the freezer for up to 3 months. When you're ready to use them, thaw the layers overnight on the countertop before frosting and serving. Note: It's best to freeze the cake unfrosted, as the frosting may not maintain its quality once frozen and thawed.