A rich and luscious dessert that will outshine all other brownie recipes you’ve made before.
Makes 24 to 32 squares
12 oz [400 g] unsalted butter (1½ cups [375 ml])
1¼ cups [310 ml] good-quality cocoa powder
2¾ cups [680 ml] granulated sugar
¾ tsp [3.75 ml] salt
2 tbs [10 ml] Kahlua (coffee liquor)
1½ tsp [7.5 ml] instant coffee granules
5 large eggs
1 2/3 cups [410 ml] all-purpose flour
¾ cup [180 ml] semisweet chocolate chips
¾ cup [180 ml] toasted, chopped walnuts
For the topping
6 oz [200 g] chopped bittersweet chocolate
4 oz [115 g] unsalted butter (½ cup [125 ml])
1 cup [250 ml] finely chopped, toasted walnuts
Preheat oven to 325°F [160°C]. Line the bottom and sides of a 9×13-inch (see note) straight-sided baking pan with heavy-duty aluminum foil, leaving about a 2-inch overhang on the short sides. Lightly butter the foil.
Put the butter in a large saucepan over medium-low heat and stir occasionally until melted, about 2 minutes. Off the heat, whisk in the cocoa powder until smooth, 1 minute. Add the sugar and salt, and whisk until well blended. Use your fingertip to check the temperature of the batter — it should be warm, not hot. If it’s hot, set the pan aside for a minute or two before continuing.
Whisk in the Kahlua and instant coffee and then the eggs, one after the other, mixing until just blended after each addition. Sprinkle the flour over the batter and stir with a rubber spatula until just blended. Stir in the semisweet chocolate chips and walnuts.
Scrape the batter into the prepared pan and spread evenly. Bake until a toothpick inserted in the center comes out with small bits of brownie sticking to it, 35 to 45 minutes. Do not overbake! Cool the brownies completely in the pan on a rack, about 3 hours.
To make the topping: Put the chopped bittersweet chocolate and butter in a small, heatproof bowl set over a small pot of barely simmering water and stir frequently until melted, about 3 minutes (alternatively, the chocolate and butter can be melted in a microwave).
Pour the glaze over the brownies and spread to within 1/2 inch of the edges using a small offset spatula. Sprinkle the walnuts over the glaze. Set the brownie aside until the glaze is firm.
Using the foil overhang, lift the brownies from the pan. Carefully peel away the foil. Cut the brownie into small squares and serve immediately, or wrap in plastic or waxed paper and refrigerate for up to 5 days (see note). Let the brownies come to room temperature before serving.
Baking pans: This recipe makes a big batch of brownies. Using a 9×13-inch [23x33-cm] pan will make thick brownies (about 2-inch [5-cm] thick). Because they are so indulgent, I prefer using two 9×9-inch pans, which make brings the brownies down to about a 1¼-inch [3-cm] thickness.
Freezing the brownies: Because this recipe makes a big batch of brownies, I like to cut them into serving-size squares (with the ganache and walnuts on), store them in an airtight container then freeze them. They keep beautifully and take just 20 minutes to defrost at room temperature.