8 ounces almond paste (Love 'n' Bake brand is gluten-free), broken up with a fork
1 cup (2 sticks) unsalted butter, melted and cooled
3/4 cup sugar
4 extra-large eggs
2 cups all-purpose gluten-free flour (I use Better Batter)
1 teaspoon xanthan gum (omit if using Better Batter)
red food coloring (6 to 8 drops liquid)
green food coloring (6 to 8 drops liquid)
1/4 cup seedless red raspberry jam (I like Polaner all-fruit, but any will do)
1 cup semi-sweet chocolate chips
2 tablespoons unsalted butter
1/3 to 1/2 cup milk or cream (not nonfat)
Preheat your oven to 350 degrees Fahrenheit. Grease 3 rectangular pans (I used 11 inch x 7 inch, but 9 inch x 12 inch work well, too) with unsalted butter and set them aside. Avoid using glass, if possible. If you do use glass pans, lower the baking temperature to about 335 degrees Fahrenheit, and monitor carefully during baking to prevent burning.
In a large bowl (or, ideally, the bowl of a stand mixer fitted with the paddle attachment), cream the almond paste, 1 cup butter, sugar, and eggs until well combined and very smooth. Add the flour and xanthan gum, and mix until the dough comes together and is smooth. It will be thick and shiny (see the photo).
Divide the dough into three parts. 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.
Place each pan, one at a time, into the preheated oven and bake for 10 minutes, or until the dough just begins to brown around the edges. It may puff up, but it will cave. We want it flat, and it will be flat. Not to worry.
Allow the layers to cool slightly in the pans. Place the green layer on a piece of parchment paper, spread evenly with one half of the jam, top with the plain layer, spread the remaining jam on top of the plain layer, and top with the red (okay, pink) layer. Cover the whole thing in plastic wrap, top with a pan that is the same size as what you baked them in. Place something heavy (I used 3 pounds of raw chicken. seriously. it was really well sealed) atop the pan to compress the layers. Refrigerate at least 8 hours, or overnight.
Once the cookies are chilled, make the ganache. Place the chocolate in a medium sized heatproof bowl. In a small saucepan, heat 1/3 cup cream and 2 tablespoons butter over medium heat 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. If the chocolate is not pourable, stir in as much of the remaining cream as necessary to make it shiny and pourable. Pour the ganache over the top of the chilled cookies, and spread with a spoon or offset spatula in an even layer.
Chill once more until the ganache is set (in the refrigerator for an hour, or the freezer for about 15 minutes). Slice with a large serrated knife into squares.
Serve chilled. To me. Serve them chilled to me.
Recipe by Gluten-Free on a Shoestring at http://glutenfreeonashoestring.com/rainbow-cookies/