- Preheat oven to 350 degrees.
- In a medium mixing bowl, combine 1/4 stick (4 tbsp.) melted butter and two eggs; beat well by hand.
- Gradually combine dry brownie mix into wet mixture beating by hand until well blended. Add coffee grounds. Let rest five minutes to allow coffee to steep into mixture.
- Spread batter evenly into a lightly greased 8-inch square pan.
- Bake for about 20 to 25 minutes or until sides of brownies begin to pull away from pan. Allow to cool completely in pan on a wire rack.
- While brownies are cooking, wash berries and dry gently with a paper towel. Cut away strawberry tops and slice thinly. Cut larger blackberries in half. Set aside.
- Combine heavy cream, sugar, and vanilla in a large, cold mixing bowl. Whip by hand or with an electric mixer until cream forms stiff peaks. Do not overmix.
- Spread whipped cream over the brownies in a thick layer, or pipe into large dollops with a piping bag. Top with berries as desired.