Grease a 6 inch cake pan with some melted butter (or another cake pan that fits in the pressure cooker). Line a parchment paper on the bottom of the cake pan.
Melt 1/2 cup chocolate chips in the microwave. Heat for 30 seconds, then at 15 seconds intervals until smooth.
Preparing the brownie batter
In a large bowl, mix melted butter & sugar. Stir until smooth.
Mix in the eggs and vanilla extract. Then add the melted chocolate & mix again.
Fold in the all-purpose flour, cocoa powder, baking powder and salt. Do not over mix.
Add 1/4 cup chocolate chips and fold them in the batter.
Transfer batter to the prepared cake pan. Top with the remaining 1/4 cup chocolate chips.
Cover the cake pan with paper towels and foil. This is important so the steam does not go into the cake batter while it is cooking.
Steaming brownie in instant pot
Add water to the instant pot steel insert. Place a trivet, and the cake pan on the trivet. Close lid with vent in sealing position.
Cook on manual or pressure cooker mode at high pressure for 35 minutes (see last note). When the pressure cooker beeps, let the pressure release naturally.
Carefully take the cake pan out using mitts. Remove the foil and paper towel. Let the brownie rest on the counter for about 10 minutes.
Check that it is done (insert a clean knife or toothpick at the center of the brownie, which should come out clean). Run a knife around the edges of the brownie. Then carefully remove the brownie from the cake pan.
Slice and serve warm with vanilla ice cream. Enjoy!
Chocolate Chips: I tried this recipe with semi-sweet chocolate chips and milk chocolate chips. My family enjoyed the semi-sweet chocolate chips much more. But feel free to take your pick. Removing the brownie: I placed the cake pan on a can of coconut milk, and the sides of the fat diddio cake pan slide out like a charm. Then as we added the parchment paper at the bottom, it came off very easily too. Cake pan: I use a removable bottom 6 inch Fat Diddio cake pan to make this cake, as it is just easier to remove the cake from it. Created: This recipe was created in a 6qt Instant Pot DUO60 Multi-use Pressure Cooker.Update: I have tried this recipe with pressure cooking for 30, 35 and 40 minutes and all worked well. Some readers reported that their brownie was not cooked in 30 minutes, so feel free to increase cooking time to 40 minutes.