Grasshopper Ice Cream Sandwiches With Hot Fudge Sauce

Preheat oven to 375 degrees F. Butter a 10-by-15-inch rimmed baking sheet; dust with flour, tapping out excess. Set aside.

In a bowl, whisk together flour, cocoa, baking powder, and salt. Cream together the butter and sugar until smooth. Add eggs and vanilla; beat until light and fluffy.

With mixer on low, gradually beat in flour mixture. Pat dough into a rectangle. Wrap in plastic and refrigerate for 30 minutes.

Roll out dough between wax paper into a 10-by-15-inch rectangle. Remove top paper; use the bottom to flip dough onto prepared sheet. Score into 20 squares with a paring knife. Pierce holes over squares.

Bake until just firm, 8 to 10 minutes, rotating sheet halfway through. Cut into squares, then let cool completely.

Sandwich ice cream between two cookies. Wrap in plastic and freeze to set, 5 to 10 minutes. Serve plain, or place on plates and drizzle with hot fudge.

For Hot Fudge Sauce: In a small saucepan, combine corn syrup and chocolate. Stir over medium-low heat until smooth, 4 to 5 minutes. Remove from heat. Whisk in heavy cream until smooth.

Serve right away, or let cool to room temperature before transferring to an airtight container (Sauce can be refrigerated for up to 3 weeks. To serve, warm over low heat or in microwave).