1 cup butter
1/2 cup sugar
4 egg yolks
1 tsp vanilla
2 1/2 cups flour
3 tsp cinnamon
liquid food coloring
Mix butter, sugar, eggs and vanilla until fluffy. Gradually add flour and cinnamon. Divide dough in 1/2 and mix desired food color into 1/2 of the batter. Roll plain batter into a disk and colored batter into a log. Cover in parchment and refrigerate until butter hardens.
Take colored dough and mold with hands to desired abstract shape. The shape does not have to be precise. Put back into the refrigerator to harden.
Remove both doughs from the refrigerator. Carefully shape plain dough around your colored dough. You might have to cut the plain dough in pieces to do this. When the roll comes together it will be very large and thick. Gently roll the dough on a cookie mat until the desired size of cookie log is reached. Refrigerate for at least an hour.
Remove dough from refrigerator and cut into slices. Place on a baking sheet and bake in a 350 degree oven for 10 minutes or until plain dough is golden brown. Cool before serving.