Step 1: Melt Butter and Chocolate

Create a double boiler by placing a heatproof bowl over a pot of simmering water. Add chopped chocolate and butter. Stir occasionally until melted and smooth (3-4 minutes). Alternatively, microwave in 30-second intervals, stirring between each. Let cool for 5 minutes.

Step 2: Combine Sugar and Chocolate

Whisk granulated sugar into the cooled chocolate mixture until well combined. The mixture will look thick and slightly grainy.

Step 3: Add Eggs and Vanilla

Add eggs one at a time, whisking vigorously after each addition until glossy and smooth. Add vanilla extract and whisk for another 30 seconds.

Step 4: Incorporate Dry Ingredients

In a separate bowl, sift together cocoa powder, flour, salt, and espresso powder. Gently fold the dry ingredients into the chocolate mixture using a rubber spatula. Mix just until no flour streaks remain.

Step 5: Pour and Spread

Pour batter into a greased and parchment-lined 9x13-inch baking pan. Spread evenly into corners with an offset spatula. Tap the pan gently on the counter 2-3 times to release air bubbles.

Step 6: Bake to Perfection

Bake at 350°F (175°C) for 25-30 minutes. Brownies are done when a toothpick inserted 2 inches from the edge comes out with moist crumbs. The center should look slightly underdone.

Step 7: Cool and Cut

Let brownies cool completely in the pan on a wire rack for at least 2 hours. For ultra-clean cuts, refrigerate for 30 minutes before slicing. Lift out using parchment overhang and cut with a sharp knife, wiping clean between cuts.