Created by Chocolatl on October 21, 2011
Step 1: Sift flour and cocoa together.
Step 2: Beat butter and brown sugar together until light and fluffy. Stir in flour mixture.
Step 3: Shape into 2 logs about 1" in diameter. Wrap well and refrigerate for 1 hour.
Step 4: Preheat oven to 350° Fahrenheit.
Step 5: Unwrap dough and cut into slices about 1/4" thick.
Step 6: Bake on ungreased cookie sheets for 8-10 minutes, or until firm but not browned. Let cool 1 minute on sheets, then remove to wire racks to finish cooling.
Step 7: To make filling, melt butter in a small saucepan over low heat. Continue cooking until butter just begins to turn brown. Remove from heat and cool slightly. Stir in powdered sugar and lime juice.
Step 8: Spread half the cookies with the filling. Place the remaining cookies on top and press down gently.