Preheat the oven to 350℉ and place a rack in the center of the oven.
Combine the eggs with the cocoa powder, salt, baking powder, espresso powder and vanilla extract. Stir to combine and set aside
In a medium sauce pan, melt the butter and add the sugar, stirring to combine.
Add the butter and sugar mix to the egg and cocoa mixture. Stir until smooth.
Add the flour and chocolate chips to the mixture. Stir until smooth.
Place the brownie batter into a greased 9"x13" baking tray
Bake for 28-32 minutes or until a toothpick inserted into the center comes out clean.
Remove from the oven and let cool.
Cut brownies into 16 equal pieces and serve. Store any leftovers in an airtight container in the fridge.