Servings: 36

Start to finish: 1 hour

5 ounces bittersweet or semisweet chocolate, chopped

2 ounces unsweetened chocolate, chopped

8 tablespoons unsalted butter, cut into 4 pieces

3 tablespoons unsweetened cocoa powder

1¼ cups (83/4 ounces) sugar

3 large eggs

2 teaspoons vanilla extract

½ teaspoon salt

1 cup (5 ounces) all-purpose flour

Adjust oven rack to middle position and heat oven to 350 F. 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.

Microwave bittersweet and unsweetened chocolates in bowl at 50% power for 2 minutes. Stir in butter and continue to microwave, stirring often, until melted. Whisk in cocoa and let mixture cool slightly.

Whisk sugar, eggs, vanilla, and salt in large bowl until combined. Whisk chocolate mixture into sugar mixture until smooth. Using rubber spatula, stir in flour until no dry streaks remain. Transfer batter to prepared pan and smooth top. Bake until toothpick inserted in center comes out with few moist crumbs attached, 35 to 40 minutes, rotating pan halfway through baking.

Let brownies cool completely in pan on wire rack, about 2 hours. Using foil overhang, remove brownies from pan. (Uncut brownies can be refrigerated for up to 3 days.) Cut into 36 squares before serving.

Fudgy Triple-Chocolate Espresso Brownies

Whisk in 1½ tablespoons instant espresso powder or instant coffee powder along with cocoa.