Make vanilla and chocolate sable doughs and chill at least 1 hour. Preheat oven to 325 degrees F.

Roll out each dough to an even 1-inch thickness about twice as long as wide.

Using a ruler and a sharp knife, cut out a 3x6-inch rectangle from each piece of dough. (Gather excess dough and set aside to make other cookies.) Cut rectangles lengthwise in thirds to make 3 bars. Stack dough in 2 layers, alternating chocolate and vanilla doughs, to form a checkerboard pattern (see below). Press and pat gently to make dough stick together. Slice cookies 1/4-to 1/3-inch thick and carefully transfer to a parchment-lined baking sheet using a spatula. (Note: make sure to keep edges of dough straight with a ruler and measure carefully.) Repeat with remaining dough or shape excess into different shapes.

Bake 15 to 20 minutes. Remove to a rack to cool.

S: About 1 Dozen