In a medium bowl, whisk together the eggs, cocoa powder, salt, baking powder, and vanilla. Set aside.
2 large eggs, 1/2 cup (40g) dutch-processed cocoa powder, 1/2 tsp salt, 1/2 tsp baking powder, 2 tsp vanilla
In a medium microwave-safe bowl, combine the butter and sugar. Heat in the microwave for 30 seconds at a time until the butter is melted.
1/2 cup (114g) unsalted butter, 1 cup (200g) granulated sugar
Stir and continue heating just until the butter starts to foam. You don't want to bring it to a boil, just heated through to melt some of the sugar which will help create that top shiny crust on top of the brownies. This should take about 1.5 -2 minutes total for the butter to melt and start to foam.
Add the hot butter mixture to the cocoa mixture. Whisk until smooth. Stir in the flour, and then stir in 1/2 cup of chocolate chips until melted. Let cool for 15 minutes.
3/4 cup (95g) all-purpose flour, 1/2 cup (85g) semi-sweet chocolate chips
Meanwhile, preheat your oven to 350F. Butter and line an 8x8" baking pan with parchment paper.
Once the batter has cooled, stir in the rest of the chocolate chips and spoon the batter into the prepared baking pan. Spread the batter out evenly in the pan.
1 cup (170g) semi-sweet chocolate chips
Bake for about 25 minutes or until a toothpick inserted into the center comes out with a few moist crumbs. The edges should be set, but the center should still look moist. Let cool before cutting into squares.