This is from the June 2007 Good Housekeeping and is so good. I made it today.
Easy Brownie Shortcake Dessert
1 pkg. (19.5 oz) brownie mix
1 16 oz.container of Breakstone's Sour Cream, divided
1 cup thawed Cool Whip Whipped topping (real stuff

)
1 Tbsp. powdered sugar
1 tsp. vanilla
3 cups cut-up mixed strawberries & blueberries
Preheat over 350 F. Prepare brownie batter as directed on package; stir in 1/2 cup sour cream. Spoon into greased & floured 9" round cake pan.
Bake 45 min; cool 10 min. Remove from pan to wire rack; cool completely.
Mix remaining sour cream, whipped topping (1 cup), sugar & vanilla. Cut brownie horizontally in half. Place bottom half on plate; spread with half of the sour cream mixtur. Cover with top of brownie, remaining sour cream mixture & fruit. Store in refrigerator.
NOTES: I chose to use Breakstone's sour cream over cheaper (they named Breakstone's in recipe) because it actually is better. Also, I chose to use the Cool Whip brand that is NOT light, fat free, sugar free, etc. The "real thing." I figured the flavor and ability to hold shape as "frosting" would be better.
Enjoy -

GG