The warm, gooey nut mixture that tops this shortbread is also fantastic over ice cream.
In a heavy small saucepan combine butter, brown sugar, and corn syrup. Bring to boiling over medium heat. Remove from heat. Stir in mixed nuts, chipotle powder, and vanilla; set aside to cool 15 minutes.
Spoon warm nut mixture on top of cookies. Let stand at least 15 minutes before serving. Makes 16 servings.