Ingredients

• 8 ounces cream cheese, room temperature
• 1/4 cup sugar
• 1 large egg, room temperature
• 1/4 teaspoon vanilla extract
• 6 tablespoons unsalted butter, plus more for pan
• 1/4 cup cornstarch
• 1/4 cup unsweetened cocoa powder
• 1 tablespoon instant coffee or espresso powder
• 1/2 teaspoon kosher salt
• 9 ounces semisweet chocolate, coarsely chopped
• 1 cup sugar
• 1 teaspoon vanilla extract
• 3 large eggs, room temperature
• An 8x8x2" baking pan

Instructions

1. Using an electric mixer on high speed, beat cream cheese and sugar in a large bowl until smooth. Add egg and vanilla and beat until smooth.
2. Preheat oven to 350°F. Butter baking pan and line with 2 overlapping layers of parchment, leaving a 2" overhang on all sides. Butter parchment.
3. Whisk cornstarch, cocoa powder, coffee, and salt in a small bowl.
4. Combine chocolate and 6 Tbsp. butter in a large heatproof bowl set over a pot of barely simmering water, stirring occasionally, until butter and chocolate are melted and smooth. Remove from heat, then stir in sugar and vanilla. Whisk in eggs, one at a time, then whisk in cornstarch mixture until smooth, about 1 minute.
5. Transfer batter to prepared pan. Dollop cream cheese mixture over batter, then swirl into batter with a knife or spatula.
6. Bake brownies until a toothpick inserted into the center comes out with a few moist crumbs attached, about 30 minutes. Transfer pan to a wire rack and let cool completely. Using parchment overhang, transfer brownies to a cutting board. Cut into 4 pieces lengthwise, then 4 pieces crosswise to make 16 bars.
7. Brownies can be made 3 days ahead. Store in an airtight container at room temperature.