Preheat oven to 350°F (175°C). Line a 9x9 inch (or 8x8 inch for thicker brownies) baking pan with parchment paper, leaving an overhang on two sides to easily lift the brownies out later. Lightly grease the exposed sides of the pan.

In a medium bowl, whisk together the flour, cocoa powder, and salt. Set aside.

In a large, microwave-safe bowl or small saucepan, melt the butter. If using a saucepan, remove from heat once melted.

Add the granulated sugar to the melted butter and whisk vigorously for about 1 minute until well combined and glossy. The sugar will not fully dissolve, but this step helps create the fudgy texture and crackly top.

Whisk in the eggs, one at a time, until just combined after each addition. Be careful not to overmix.

Stir in the vanilla extract. The mixture should be thick and shiny.

Gradually add the dry ingredient mixture to the wet ingredients, folding with a rubber spatula until just combined. Do not overmix; overmixing can lead to tough brownies.

If using, gently fold in the chocolate chips.

Pour the batter evenly into the prepared baking pan.

Bake for 25-30 minutes for an 8x8 pan, or 20-25 minutes for a 9x9 pan, or until a toothpick inserted into the center comes out with moist crumbs, but not wet batter. The edges should be set, and the center may still be slightly jiggly.

Let the brownies cool completely in the pan on a wire rack before lifting out with the parchment paper overhang and cutting into squares. This is crucial for fudginess and clean cuts.