Beat cream and powdered sugar in a medium bowl with an electric mixer on high until stiff peaks form. Fold in 2 Tbsp. liqueur; set aside.

Beat milk, pudding mix and remaining 4 Tbsp. liqueur in another medium bowl for 1 to 2 minutes or until smooth.

To assemble, cut each brownie into 8 cubes. Spoon about 2 Tbsp. pudding mixture into each of 6 (8-oz.) trifle dishes. Layer with half of the brownie cubes and remaining pudding mixture, then remaining brownie cubes. Top with whipped cream mixture.

Cut mints lengthwise into thin shards using a sharp knife. Sprinkle on top of trifles. If desired, refrigerate up to 4 hours before serving.