Cream the butter and sugar until combined on medium speed on a stand mixer. Slowly add the eggs and mix until combined.

Add the salt, extract, and almond flour and mix to combine. Give the bottom of the mixing bowl a good scrape to ensure the ingredients are combined.

Add the flour in two to three additions and mix just until the dough comes together. Wrap the dough in plastic wrap and refrigerate.

Repeat the steps for the chocolate dough. Add the cocoa powder with the all purpose flour and add in two to three additions. Chill both doughs in the refrigerator firm, about an hour or two.

On a lightly floured surface, roll our each dough into a 3/8" thick.

Brush the top chocolate dough with the lightly whisked egg white. Lay the vanilla dough on top. If the dough is getting soft, place it back into the refrigerator until solid.

Slice the dough into two inches strips. At this point, you should have 4 - 2" wide strips. Stack one of the strips onto another with the egg white to use as glue. Make sure to alternate the layers. Again, if the dough has softened, refrigerate until firm.

Slice the block into quarters, lengthwise. Lay one strip down and alternate the layers on top to create the checkerboard look. You should now have a 4x4 checkerboard. Use the egg white to stick the layers together. Wrap and refrigerate until solid.

Preheat the oven to 350F. Prepare a baking sheet pan with parchment or silpat.

Slice the dough into 1/4" thick pieces. Bake for 12 minutes until the edges are a light golden brown.