Pour 1.5 c of water into your Instant Pot and put your vegetable steamer basket inside.
Wash your broccoli and cut off stalk, into smaller pieces.
Put into steamer basket, close lid and steam valve and set to high pressure for 1 minute. *alternatives* Set for 0 minutes if you still like a bit of crunch to it, or 2 minutes if you like your broccoli VERY soft or you have more than 2 heads cooking at one time. Do not overfill pot past 3/4 mark inside pot.
Do a quick release and lift out basket, pour florets into a bowl.
Pour melted butter on top and sprinkle parmesan cheese on and serve.