For serving: sliced bananas, chopped toasted nuts, honey for drizzling
Grease the insert of a 6-quart Instant Pot with nonstick cooking spray.
Add the milk, water, mashed bananas, oats and salt to the pot and give the mixture a good stir.
Secure the lid making sure the valve is sealed. Select the Manual or Pressure Cook button and dial up or down to 4 minutes. The IP will start automatically. When finished cooking, let the pressure naturally release for 15 minutes before manually releasing the remaining pressure (otherwise the oatmeal may spurt through the valve if pressure is released too soon). Stir in the brown sugar (or honey) and vanilla.
Serve warm with additional milk (if desired), sliced bananas, chopped nuts or extra honey/brown sugar. The oatmeal will thicken considerably as it cools.
Consistency: you can increase the liquid (milk or water) if you like a thinner consistency to steel cut oats.Slow Cooker: I haven't made this steel cut oats recipe in the slow cooker, but it should convert pretty well based on this similar Creamy Coconut Milk Steel Cut Oatmeal recipe.Burn Warning on Instant Pot: If you are getting the burn warning when cooking, you can help/fix that by adding more water. You can add up to another cup of water with good results (the oats will look runnier after cooking but will thicken as they cool).