Step 1

Preheat the oven to 350˚F (180˚C).

Step 2

Add the butter and 1 cup (175 g) of chocolate chips to a large microwave-safe bowl. Microwave for 1½ minutes, then let sit for 3 minutes before whisking together.

Step 3

Add the granulated and brown sugars, vanilla, and salt. Whisk to combine.

Step 4

Whisk in the eggs until fully combined.

Step 5

Sift the flour and cocoa powder into the bowl and fold in with a spatula. Add the remaining chocolate chips and fold to incorporate.

Step 6

Line a 9-inch (23-cm) square baking pan with parchment paper and grease with nonstick spray. Spread the batter evenly in the pan.

Step 7

Bake for 35-40 minutes, until a toothpick inserted in the center comes out with a few moist crumbs attached.

Step 8

Let cool completely before cutting.

Step 9

Enjoy!