Chocolate Pinwheel Cookies

These can be made as chocolate-and-vanilla or chocolate-and-mint, your choice!

• 1/2 cup butter
  
• 1/2 cup sugar
  
• 3 tablespoons milk
  
• 1 egg yolk
  
• 1/2 teaspoon vanilla
  
• 1 1/2 cup flour
  
• 1 1/2 teaspoon baking powder
  
• 1/8 teaspoon salt
  
• 1 square unsweetened chocolate
  
• 1/2 teaspoon peppermint extract (optional)
  
• Green food coloring (optional)
  

Cream butter and sugar. Beat in milk, egg yolk and vanilla. Mix dry ingredients and stir into dough. Divide in half. Add melted chocolate to half; if desired, add peppermint extract and green food coloring to other half. Roll on waxed paper into two large rectangles, stack chocolate dough on the other half. Roll up jellyroll style, wrap and chill several hours. Slice into 1/4 inch slices and bake at 375 degrees for 8-10 minutes.