1. Preheat oven to 350°. Place paper baking cups in miniature muffin pans. Microwave 1/2 cup chocolate morsels and 1/2 cup butter in a microwave-safe bowl at HIGH 1 to 2 minutes or until butter melts, stirring after 1 minute. Stir until chocolate melts. Whisk in 1/2 tsp. vanilla and next 3 ingredients.
2. Combine flour and baking powder; gradually stir into chocolate mixture. Using a small scoop, place 1 level Tbsp. batter in each baking cup. Bake at 350° for 15 minutes. Let cool in pans 5 minutes. Remove from pans to wire racks, and cool completely (about 20 minutes).
3. Meanwhile, combine powdered sugar, peanut butter, 2 Tbsp. softened butter, and remaining 1 tsp. vanilla in a medium bowl; beat at medium speed with an electric mixer until smooth.
4. Roll peanut butter mixture by teaspoonfuls into 32 balls. Press 1 ball into top of each brownie, flattening slightly.
5. Place remaining 1/2 cup chocolate morsels in a medium bowl. Microwave cream in a 1-cup glass measuring cup at HIGH 1 minute. Pour cream over chocolate morsels; stir until smooth. Let cool until slightly thickened. Spread 1 to 2 tsp. chocolate mixture over peanut butter and brownie, spreading almost to edges of baking cup. Let cool 1 hour or until set.