• Preheat oven to 350 F. Spray three rimmed quarter sheet baking pans (9×13 sheet pans) with cooking spray and then line with parchment paper.
• Using a stand mixer or hand mixer, cream the almond paste with ¾ cup sugar on low speed until well combined, about 2-3 minutes. Add butter and beat on medium speed until light and fluffy, about 2 minutes.
• Add in egg yolks, almond extract, and salt and continue to beat until incorporated.
• Reduce the mixer speed to low and add the flour. Mix until just combined.
• In another mixing bowl, whip the egg whites at medium-high speed until they just hold stiff peaks. Then add the remaining ¼ cup sugar and beat on high speed until they form stiff, glossy peaks, about 2-3 minutes.
• Fold the egg whites into the batter. Divide the batter evenly into 3 mixing bowls. You can use a kitchen scale to accurately divide the batter into thirds.
• Stir in a few drops of red food coloring into one bowl and a few drops of green food coloring into another, leaving the last bowl plain. Note that the batter will bake up darker than it looks when raw.
• Pour the batter from each of the bowls into a separate prepared pan. Use a small icing spatula to spread the batter into an even thin layer.
• Bake each layer for 8-10 minutes, until the edges just start to brown. Allow the cakes to cook in the pan for 10 minutes, then carefully transfer to a wire cooling rack to cool completely.

ASSEMBLE

• Line a large half sheet baking pan with parchment paper. Carefully invert the green layer onto the lined baking sheet and peel off the parchment paper. Spread half of the preserves or jam over the cake.
• Flip the white layer on top of the green layer and peel off the parchment paper. Spread with remaining preserves on top. Invert the red layer on top of white layer and peel off the parchment paper.
• Cover the pan tightly with plastic wrap and place a quarter sheet pan on top facing up, with heavy objects evenly distributed on top to weigh down the cake. Refrigerator for at least 8 hours or overnight.

CHOCOLATE

• Remove the weights and plastic wrap.
• Melt chocolate in a microwave-safe bowl in 30-second increments, until smooth.
• Use a small icing spatula to quickly spread half of the melted chocolate in a thin layer on top of the cake. Place the cake back in the fridge to allow the chocolate to set, about 15 minutes.
• Once set, invert the cake to another parchment baking sheet. Quickly spread with the remaining melted chocolate (if the chocolate has set, just pop it back in the microwave to melt again before spreading). Allow the chocolate to set in the fridge, for about 30 minutes. You can also place it into the freezer to set it quicker.
• Once set, use a serrated knife to trim the edges to even them out. Then cut into 1.5-inch rectangles (cut 8 rows crosswise and 6 rows lengthwise) and serve.