Prepare the Sponge Cake Layers:

1. Preheat your oven to 325°F. Grease (cooking spray) and line three 9×13-inch baking pans with parchment paper. Leave a 2-inch overhang of parchment paper. These will act as handles when removing the cakes.
2. In a mixing bowl, beat the egg yolks, sugar, and extracts until pale and creamy. Set aside. 
3. In another bowl, beat the egg whites until stiff peaks form. Set aside. 
4. Heat the almond paste in 20-second increments in the microwave until soft, but not melted. Cream the softened butter and softened almond paste in a separate bowl until very smooth.
5. Gently fold the egg yolk mixture into the almond paste mixture until well combined.
6. Gradually sift in the flour and salt until you have a smooth batter. Scraping down the sides of the bowl as needed.
7. Gently fold the egg whites into the flour mixture until you get a smooth batter. 
8. Divide the batter into three equal portions. If you want precise color layers, set each bowl on a kitchen scale, set it to zero, and weigh the batter in each bowl so it is the same weight.
9. Color one portion with red food coloring (I like redish-pink color) and another portion with green food coloring. Leave one portion uncolored.
10. Spread each colored batter into its prepared baking pan.
11. Bake for 10-12 minutes or until the edges are lightly golden and a toothpick inserted into the center comes out clean. Allow the cake layers to cool completely.

Assemble the Rainbow Cookies:

1. Slightly heat the jam in the microwave to make it easer to spread across the cake. Spread half of the jam evenly over the green layer.
2. Place the uncolored cake layer on top of the jam-covered green layer. Unmold the plain cake layer by inverting it onto another pan or cutting board; peel off the parchment. Spread the remaining jam mixture over this layer.
3. Finally, place the red layer on the jam-covered layer, creating a “sandwich” of cake layers. Press down gently to adhere.

Chill:

1. Cover the cake with plastic wrap and cover with a baking sheet pan. On top of the sheet pan, add a few heavy plates to weigh down the cake. Refrigerate for at least 4 hours, or overnight.

Chocolate Topping & Chill Again:

1. Remove rainbow cookies from the fridge. Take off the weights and plastic wrap.
2. Spread a thin, even layer on melted chocolate over the top of the cake. Spread in an even layer. Refrigerate until set for 30 minutes.
3. Once the chocolate layer is solid, place a large cutting board on top of the cake and flip it to unmold onto the cutting board, discard the bottom layer of parchment, and spread the remaining melted chocolate in an even layer over the surface. 
4. Optional: wavy pattern: scrape wavy lines into the chocolate with a fork. 
5. Return to the refrigerator and chill until set for 30 additional minutes.

Cut and Serve: 

1. Once chilled, use a sharp knife to trim the edges of the cake to create neat edges. After each cut, run the knife under hot water and dry it with a damp cloth to get clean cuts every time. 
2. Cut the cake into small, 1 1/2-inch squares and serve. Store in an airtight container at room temperature for up to 1 week.

Enjoy your classic Italian Rainbow Cookies! They are not only visually stunning but also incredibly delicious.