Christmas Butter Swirl Cookies - Festive Holiday Treats - Recipes by Clare

Ingredients

• 1 cup unsalted butter, room temperature.
• 1 cup powdered sugar.
• 2 egg yolks.
• 1 tsp vanilla extract.
• 1/2 tsp salt.
• 1 1/4 cup all-purpose flour (for white dough).
• 1 cup all-purpose flour (for chocolate dough).
• 1/4 cup unsweetened cocoa powder.