Why this recipe works:
Cream cheese brownies are an American classic. However, to be done right, the two batters must complement each other rather than compete. We use unsweetened chocolate for bold chocolate flavor and a cakey brownie batter so that the added liquid from the cream cheese filling doesn’t make the brownies soggy or too dense. The addition of sour cream to the cream cheese swirl adds a pleasing tang that complements the brownies’ sweetness. The usual method of dolloping cream cheese over the brownie batter before swirling delivers a soggy center and dry edges. To ensure even baking and the right balance of cream cheese swirl and chocolate in every bite, we spread the cream cheese mixture evenly over the brownie batter and then dollop reserved brownie batter on top before swirling.
NOTE: To accurately test the doneness of the brownies, be sure to stick the toothpick into the brownie portion, not the cream cheese. Leftover brownies should be stored in the refrigerator. Let leftovers stand at room temperature for 1 hour before serving.
Cream Cheese Filling
4 ounces cream cheese, cut into 8 pieces
1/2 cup sour cream
2 tablespoons sugar
1 tablespoon all-purpose flour
2/3 cup (3 1/3 ounces) all-purpose flour
1/2 teaspoon baking powder
1/2 teaspoon salt
4 ounces unsweetened chocolate, chopped fine
8 tablespoons unsalted butter
1 1/4 cups (8 3/4 ounces) sugar
2 large eggs
1 teaspoon vanilla extract
1. FOR THE CREAM CHEESE FILLING: Microwave cream cheese until soft, 20 to 30 seconds. Add sour cream, sugar, and flour and whisk to combine. Set aside.
2. Adjust oven rack to middle position and heat oven to 325 degrees. Make foil sling for 8-inch square baking pan by folding 2 long sheets of aluminum foil so each is 8 inches wide. Lay sheets of foil in pan perpendicular to each other, with extra foil hanging over edges of pan. Push foil into corners and up sides of pan, smoothing foil flush to pan. Grease foil.
3. FOR THE BROWNIE BATTER: Whisk flour, baking powder, and salt together in bowl and set aside. Microwave chocolate and butter in bowl at 50 percent power, stirring occasionally, until melted, 1 to 2 minutes.
4. Whisk sugar, eggs, and vanilla together in medium bowl. Add melted chocolate mixture (do not clean bowl) and whisk until incorporated. Add flour mixture and fold to combine.
5. Transfer 1/2 cup batter to bowl used to melt chocolate. Spread remaining batter in prepared pan. Spread cream cheese filling evenly over batter.
6. Microwave bowl of reserved batter until warm and pourable, 10 to 20 seconds. Using spoon, dollop softened batter over cream cheese filling, 6 to 8 dollops. Using knife, swirl batter through cream cheese filling, making marbled pattern, 10 to 12 strokes, leaving 1/2-inch border around edges.
7. Bake until toothpick inserted in center comes out with few moist crumbs attached, 35 to 40 minutes, rotating pan halfway through baking. Let cool in pan on wire rack for 1 hour.
8. Using foil overhang, lift brownies out of pan. Return brownies to wire rack and let cool completely, about 1 hour. Cut into 2-inch squares and serve.