Preheat the oven to 350 degrees and lightly grease a sheet (12X18-inches) and set aside.

In a large microwave-safe bowl, add the butter and 1 lb of chocolate. Microwave in 1-minute intervals, stirring after each one, until it is melted and smooth. Add the sugar and mix in.

Add in the eggs and vanilla, and whisk until large bubbles pop at the surface – it will go from looking slightly curdled to really glossy and thick, so keep stirring until you see this result.

In another bowl, whisk the flour, baking powder, and salt together.

Add the dry ingredients to the chocolate batter and mix once or twice. With dry streaks remaining, add the chocolate chips and mix until well-combined.

Spread the batter evenly in the prepared pan.Bake at 350 degrees for 25-30 minutes until edges are set but the middle is still slightly gooey.

Allow brownies cool completely in the pan. Serves at least 24.