1 1/2 cups granulated sugar
1/3 cup unsweetened cocoa powder
1 (5 ounce) can evaporated milk
1/4 cup (1/2 stick) butter or margarine
1 cup (6 ounce) mint-flavored semisweet chocolate chips
16 round chocolate sandwich cookies

Line an 8-inch square pan with foil; grease foil.

Mix sugar and cocoa in heavy 3-quart saucepan. Stir in milk and butter. Bring to a boil over medium heat, stirring constantly. Without stirring, boil vigorously for 5 minutes. Remove from heat; add chips and stir until melted and smooth. Spread 1 cup in lined pan, top with cookies, then spread remaining fudge evenly over top.

Refrigerate 6 hours until firm.

Invert pan, peel off foil, invert fudge and cut in 1-inch squares.