• Preheat your oven to 350°F. Line 3 quarter sheet pans (each 9-inches x 12-inches) with unbleached parchment paper, and set them aside.

Make the cookie dough.

• In the bowl of a stand mixer fitted with the paddle attachment (or a large bowl with a hand mixer), cream the almond paste and butter until well-combined. There may be some remaining small clumps in the almond paste, which is fine. Add the sugar and eggs, beating to combine well after each addition. The batter should be thick.
• Add the flour, xanthan gum and kosher salt, and mix until the dough comes together and is smooth.
• Divide the dough into three equal parts (each about 500 grams).
• Add the green food coloring to one part, and mix to combine.
• Add the red food coloring to another part, and mix to combine.
• Divide the 3 parts of dough among the three prepared pans.
• Stretch and press the dough into an even layer in each pan, using wet fingers and a wet spatula. The dough will be sticky.

Bake and assemble the layers.

• Place each pan, one at a time, in the center of the preheated oven and bake for 10 minutes, or until the dough just begins to brown around the edges. Allow the layers to cool slightly in the pans.
• Carefully place the green layer on a piece of parchment paper, spread evenly with one half of the jam.
• Place the plain layer carefully on top, taking care not to handle the cakes too much or they may begin to crack.
• Spread the remaining jam on top of the plain layer, and top with the pink layer.
• Place a sheet of parchment paper on top, and place a few books on top of the stack to compress the layers.
• Place the stack of cakes in the refrigerator for about 30 minutes, or until the layers have begun to flatten and compress.

Make the chocolate topping.

• Place the chopped chocolate in a medium-size heat safe bowl. In a small saucepan, heat the cream and butter over medium-low heat, stirring frequently, until the butter is melted and the cream is just beginning to simmer.
• Pour the hot cream and butter mixture over the chocolate, mixing to combine. The chocolate should be smooth and shiny.
• Pour the melted chocolate over the top of the chilled cookies, and spread into an even layer with an offset spatula or knife. Chill once more in the refrigerator until the chocolate topping is set (about 20 minutes).
• Using a large serrated knife, trim all of the edges and then slice into about 21 even rectangles.
• Serve immediately or wrap tightly and store in the freezer until ready to serve.