Butter each ramekin or use cooking/baking spray.
Cut the butter into slices and place it in a large microwave-safe bowl along with the white chocolate chips and semi-sweet chocolate chips. Microwave 20 seconds at a time, stirring after each 20-second interval. Mix well. It should take about 2 minutes.
Add the powdered sugar to the melted butter-chocolate mixture. Mix well.
Add one egg at a time. Then add the vanilla extract, flour, salt, and red food coloring. Mix well.
Fill the ramekins evenly, almost to the top. These do not rise.
Add one cup of water to the instant pot and place the trivet inside.
Place the filled ramekins on the instant pot trivet and secure the lid. Make sure the vent is sealed.
Press the "pressure cook" function and cook for 9 minutes.
Once the 9 minutes are up, do a quick release. Once all of the steam releases, remove the ramekins from the instant pot using gloves or a towel. They will be very hot.
Run a knife through the ramekins and serve immediately. Enjoy with powdered sugar or vanilla ice cream.