Preheat your oven to 350 degrees Fahrenheit (175 degrees Celsius) and line an 8x8 inch baking pan with parchment paper, leaving a slight overhang for easy removal.

In a large mixing bowl, whisk together the melted butter and granulated sugar until well combined. The mixture should look slightly grainy but fully incorporated.

Add the room temperature eggs one at a time, whisking vigorously after each addition. Stir in the vanilla extract until the batter becomes smooth and glossy. This vigorous whisking helps create that coveted crackly top.

Sift the cocoa powder, all-purpose flour, and salt directly into the wet ingredients. Gently fold the dry ingredients into the batter using a rubber spatula just until no dry streaks remain. Be careful not to overmix.

Fold in the semi-sweet chocolate chips if using, then pour the thick batter into your prepared baking pan, smoothing the top into an even layer.

Bake for 20 to 25 minutes. A toothpick inserted into the center should come out with a few moist crumbs attached, not wet batter. Let the brownies cool completely in the pan before slicing.