Put pressure cooker on saute mode (brown/sear for Crockpot Express), add butter and allow to melt. Then turn pot off.
Add rice and stir so it is coated. Add coconut milk, regular milk, 1/4 c coconut, water, and sugar. Stir. (if making dairy free use almond milk and coconut evaporated milk alternatives)
Close pressure cooker lid and seal steam valve. Set to pressure high for 14 minutes.
Do a quick release when done.
Remove lid and press saute again.
Whisk together your evaporated milk and egg in a small bowl. Add a bit of your warm ingredients from the pot into your egg mixture to temper it.
As soon as the rice pudding is bubbling add half milk/egg mixture and stir gently to combine. Add remaining 1/4 c. coconut, followed by remaining milk/egg mixture. You need to do this quickly so it doesn't burn on the bottom.
Allow to bubble. Stir gently. Turn pot off immediately and transfer to bowls so it doesn’t continue to cook and enjoy or refrigerate and then eat when cold.