- nonstick vegetable oil spray
- 1/2 c. unsalted butter, diced
- 3 oz. unsweetened chocolate, chopped
- 1-1/2 c. sugar
- 3 large eggs
- 1 tsp. instant espresso powder
- 1-1/2 tsp. vanilla
- 1/4 tsp. salt
- 3/4 c. flour
- powdered sugar, to sprinkle on the finished brownie hearts
- 1/2 c. unsalted butter, at room temperature
- 12 oz. raspberries, fresh or frozen
- 1/2 tsp. freshly squeezed lemon juice
- 3-1/2 c. powdered sugar
- pinch of kosher salt
- 1 to 2 T. milk, if needed to thin out the frosting
Preheat oven to 325°.
Fold a long piece of heavy foil into a 13″ wide strip and fit it inside a 9″ x 13″ metal baking pan, leaving foil overhang on the 2 long sides. Spray the foil with nonstick spray.
Stir the butter and chocolate in a large heavy saucepan over very low heat until chocolate is melted. Remove from heat and whisk in the sugar, and then the eggs, 1 at a time. Whisk in espresso powder, vanilla, and salt. Then sift the flour over the chocolate mixture and stir to blend well. Transfer batter to prepared pan.
Bake brownies until slightly puffed and dry-looking and tester inserted into center comes out with some moist batter attached, about 20 minutes. Let cool completely in pan on rack.
Cook the raspberries in a medium saucepan over medium heat, stirring frequently until the raspberries are broken down into a sauce. Pour the sauce through a fine mesh strainer to remove the seeds, and then pour the raspberry sauce back in the pot. Simmer until the sauce reduces to a 1/4 cup. It will be a very rich red and concentrated sauce. Set aside to cool. With a mixer, cream the butter with a paddle attachment on medium high speed about 2 minutes, until lightened in color and a bit fluffy. Add 2 cups of powdered sugar, the 1/4 cup of cooled raspberry sauce, lemon juice, and salt. Mix until smooth. Add another 1-1/2 cups of powdered sugar and mix until smooth. If you want the frosting less stiff, add some milk, 1 tablespoon at a time. I did not add any milk to mine, and thought it was perfect for piping. Fit a pastry bag with a medium-large round tip (I used a Wilton #12) and fill with fresh raspberry buttercream.
Run a knife around the inside edge of the brownie pan. Use the overhanging foil as an aid and gently lift the brownies from the pan. The pan I used produces a brownie that is 1/2″ thick. Be sure your cookie cutter is taller than 1/2″. Press heart-shaped cookie cutters (the cookie cutters used in my photos measure 3″ wide and 1-1/2″ wide) firmly into the cooled brownie. Use a thin metal spatula to lift the cookie cutter filled with brownie from the foil. Gently press the brownie out of the cookie cutter. Repeat the cutting process until your brownie looks like a big piece of swiss cheese. (And I hope you’re eating up some of those brownie scraps!)
With the pastry bag filled with fresh raspberry buttercream, pipe a line of frosting around the inside edge of one of the brownie hearts. Then fill in the inside of the line with frosting, too. Top with another brownie heart, very gently pressing down to make a sandwich. Repeat until all your brownie hearts are completed. To finish off, sprinkle the brownie hearts with powdered sugar. I like to fill a small hand sieve with powdered sugar and gently tap the side of the sieve to let the powdered sugar rain down.