1 pkg. (18.5 oz.) caramel, butter brickle, spice or yellow cake mix with pudding in mix
3 tbsp. Dutch process cocoa
3/4 c. water
1/4 c. chocolate or caramel flavored liqueur (or use 1 c. water instead of the 3/4 c. and omit liqueur)
3 eggs
1/3 c. oil
Butterscotch Filling and frosting (recipe follows)

BUTTERSCOTCH FILLING AND FROSTING:

In saucepan, heat to boiling 1/4 cup light corn syrup with 3 tablespoons water. Remove from heat and stir in 1 package (12 oz.) butterscotch morsels until smooth and melted. Stir in 2 tablespoons butter. Spread immediately on cake.

Mix cake and cocoa in large bowl. Add water, liqueur, eggs and oil. Beat at low speed until mixed. Increase speed to high and beat about 2 minutes until light and fluffy, scraping bowl. Butter and flour a 9-inch spring-form pan. Turn cake mixture into pan. Smooth top. Bake at 350 degrees for about 1 hour or until a tester inserted in center comes out clean. Cool on rack 15 minutes. Remove from pan and cool thoroughly 2 to 3 hours. With long knife, split cake into 3 layers. Spread 2 layers with 1/4 cup butterscotch filling. Stack on cake plate so that bottom layer is on top (to make perfectly flat). Put strips of waxed paper just under and around edges of cake on serving plate. Pour remaining frosting over top. Smooth sides and top to even thickness. Let set. Remove waxed paper. Cut in wedges to serve.