Marble Sugar Cookies

Adapted from Joy of Cooking
Yield: 3 dozen cookies

1/2 cup butter, at room temperature
1/2 cup superfine sugar
1/4 tsp salt
1 egg
1 tsp vanilla
1 1/4 cup flour
1 ounce melted and cooled semisweet or bittersweet chocolate
  1. Cream butter, sugar, and salt together until very fluffy and well blended.
  2. Add the egg and vanilla, and beat until well combined.
  3. Add flour and beat in until just combined.
  4. Take one quarter of the dough and mix in the melted chocolate.
  5. Divide the chocolate dough into 6 portions and press into the remaining three quarters of dough. Knead the doughs together slightly to create a marbled effect.
  6. Divide the dough in half and wrap in plastic wrap. Refrigerate until firm, at least 1 hour.
  7. Preheat oven to 375F.
  8. Lightly flour the work surface.
  9. Roll the dough to 1/8 inch thick. Cut dough into desired shapes.
  10. Place cookies onto a parchment lined baking sheet, about 1/2 inch apart.
  11. Bake 5 to 6 minutes or until the cookies are light golden brown at the edges.
  12. Using an offset spatula, immediately transfer the cookies to rack to cool.