In your Instant Pot place 2 cups of water in the bottom (as if you are about to steam in it) and place your steaming shelf on top.
Set to the sauté function.
On top of this add a mixing bowl (it must be a round bowl that fits well) and add to it your butter and chocolate. Melt the chocolate and the butter and mix well.
Remove the bowl from the heat and allow to cool.
After it has had about 5 minutes of cooling time add to it the eggs, sugar, cocoa powder and vanilla essence.
Slowly stir in the flour and place the bowl back on the steaming shelf in the Instant Pot.
Place the lid on the Instant Pot and set to sealing and cook for 10 minutes on the manual setting.
Once cooked, manually release pressure and then place on a cooling rack to cool down. When cool chop into brownie squares.