Brownie Raspberry Ice Cream Cake

1 (24 ounce) box fudge brownie mix, prepared as directed
1/2 cup chopped walnuts, toasted, if desired
2 ounces semisweet or bittersweet baking chocolate, chopped
1 1/2 quarts vanilla ice cream, slightly softened
2 1/2 cups individually-quick frozen unsweetened raspberries (from a 12 ounce bag), NOT thawed

Heat oven to temperature called for on brownie mix. Grease bottom of two 8” layer-cake pans; line bottoms with wax paper or foil and grease. Have ready an 8” springform pan. Stir nuts and chocolate into batter. Divide batter between layer-cake pans. Bake 30 to 35 minutes until a wooden pick inserted in centers comes out clean. Cool in pans on a wire rack for about 10 minutes, then run a knife around edges of layers and invert on rack. Peel off paper; cool layers completely.

To assemble: Select 10 to 12 whole berries; keep frozen. Place 1 brownie layer in bottom of springform pan. Top with half the ice cream; sprinkle with half the remaining raspberries. Press into an even layer with back of a spoon. Cover with remaining brownie layer; sprinkle with remaining raspberries, top with remaining ice cream and press into an even layer. Push reserved raspberries into the ice cream. Cover pan tightly with foil and freeze at least 8 hours or up to 2 weeks.

Three to 4 hours before serving: Run a knife between cake and springform pan; remove pan sides. Leave cake on pan bottom or loosen with a pancake turner and carefully transfer to a serving plate. Cut cake in wedges; leave assembled. Place in freezer. About 20 minutes before serving: Transfer cake to refrigerator to soften lightly.

NOTE: May be frozen up to 2 weeks.