IMPORTANT: This is an unusual technique and it might not work for your particular model of Instant Pot. You need to have an electric pressure cooker that keeps the heating element on even when there's no pressure and doesn't display burn notice if you look at it funny!There are many people who have successfully used this technique and shared their results with me on facebook so it works! But it really depends on your model of Instant Pot.Here's my model of Instant Pot.
Press sauté button and add the butter to the Instant Pot.
Let the butter melt halfway, turn off the sauté function and add the chocolate chips.
Mix with a spatula until the butter and the chocolate are fully melted together.
Add the sugar and mix well.
Test to see that the mixture isn't too hot. If it's too hot, then let it cool for a few minutes. Once the mixture cooled, add the eggs and mix until fully incorporated.
Add the cocoa powder, flour, and mix just until the mixture comes together. Do not over mix.
Run a silicone spatula (or a silicone scraper) along the sides of the ceramic insert to clean them up as much as possible.
Close the lid. It does not matter if the valve is turned to sealing or not as the pot will not get pressurized anyway.
Make sure to choose LOW pressure for Instant Pot. Set the time to 30 minutes.
It'll take about 3-5 minutes for Instant Pot to heat up and then it'll start cooking and the countdown will start.
Once Instant Pot beeps that the cooking of 30 minutes is done, open the lid, remove the ceramic insert from Instant Pot and let cool for about 10 minutes. Carefully slide a long silicone spatula around the edges of the Instant Pot Brownies a few times to loosen them. Try to bend the spatula and slide under the bottom of the brownie as much as possible.
Invert the ceramic insert onto a plate and hopefully the brownie will come out in one piece. I usually lose a few pieces as they stick to the bottom of the pot but the rest of the brownie comes out in one piece.
NOTE: These Instant Pot Brownies taste more cakey right after baking and get a bit fudgier after a few hours.
I prefer to use less than 3/4 cup sugar as I like less sweet desserts. I usually make these brownies with 1/2 cup + 1/8 cup sugar.
The reason for adding sugar before the eggs is that sugar cools the mixture so that the eggs can be added almost right after without scrambling them.
I use a silicone spatula similar to this design to get the brownie out of Instant Pot. It is thin and slides well around the edges. It is also long and bendy so it can even slide under the brownie.
ATTENTION: read all the comments and instructions. Not all models of Instant Pot will work with this technique!