Mazzio's Buffet Brownies Recipe

Preheat and prepare pan

Preheat the oven to 350°F (175°C). Line a 13x18-inch rimmed baking sheet (full sheet pan) or two 9x13-inch pans with parchment paper, leaving an overhang for easy removal. Lightly butter or spray the parchment.

Melt chocolate and butter

Place the unsalted butter and semisweet chocolate chips in a heatproof bowl. Melt together over a simmering water bath (double boiler), stirring occasionally until smooth, or microwave in 30-second bursts, stirring between bursts, until fully melted and glossy. Remove from heat and let cool 2–3 minutes.

Combine sugars and eggs

Stir the granulated sugar and light brown sugar into the slightly cooled chocolate-butter mixture. Add the eggs one at a time, whisking or beating well after each addition until the mixture is smooth and slightly thickened. Stir in the vanilla extract.

Add dry ingredients

Whisk together the all-purpose flour, unsweetened cocoa powder, espresso powder (if using), and salt in a separate bowl. Sift or gradually fold the dry mixture into the chocolate mixture with a rubber spatula, mixing just until no streaks of flour remain. Do not overmix.

Fold in add-ins

Fold in the chopped nuts and chocolate chunks, reserving a handful to sprinkle on top. The batter will be thick and glossy.

Spread batter and finish

Pour the batter into the prepared pan(s) and use an offset spatula to spread it into an even layer about 3/4 to 1 inch thick (for buffet-size squares you want a slightly thicker slab). Sprinkle the reserved chocolate chunks evenly over the top and lightly press them into the batter. Finish with a light sprinkle of coarse sea salt across the surface.

Bake

Bake in the preheated oven for 22–30 minutes for a full sheet or 25–35 minutes for 9x13 pans. Begin checking at the lower end of the time range: the brownies are done when the edges are set and a toothpick inserted into the center comes out with a few moist crumbs (not wet batter). Avoid overbaking to keep fudgy texture.

Cool before cutting

Remove the pan from the oven and place on a wire rack. Allow the brownies to cool completely in the pan (at least 1–1.5 hours). Use the parchment overhang to lift the slab from the pan and transfer to a cutting board.

Cut into buffet-style squares. For a 13x18-inch pan, cut into approximately 48 pieces (6x8 grid) for generous squares or 60–72 smaller squares as needed.

To store, arrange in an airtight container in a single layer or separated by parchment. At room temperature they keep well for 3 days. Refrigerate up to 1 week, or freeze airtight for up to 3 months. Bring to room temperature before serving for best texture.