Generously coat the inside of a 6-quart Instant Pot with nonstick cooking spray or softened butter.
Add the steel-cut oats, water and vanilla extract. Stir thoroughly, making sure no oats remain stuck to the bottom.
1 cup regular steel cut oats, 2 1/2 cups water, 2 tsp vanilla extract
Place the prepared apple spirals upright in the oatmeal mixture, keeping each apple together.
3 medium firm apples
In a small bowl, combine the brown sugar, cinnamon and nutmeg. Sprinkle over the tops of the apples, allowing some to fall into the centers and surrounding oatmeal.
1/4 cup brown sugar, 1 tsp ground cinnamon, 1/2 tsp ground nutmeg
Place the butter pats over the apples and distribute any remaining butter over the oatmeal. Do not stir.
3 Tbsp salted butter
Secure the lid and set the valve to Sealing. Cook on High Pressure for 15 minutes. The pot will take approximately 10 minutes to reach pressure before the cooking countdown begins.
Follow your model’s instructions for releasing pressure when cooking oatmeal. Instant Pot recommends natural release because oatmeal can foam and splatter. See My Testing Notes below for the method I tested.
Once the float valve drops, carefully remove the lid. Use a potato masher or sturdy spoon to gently break apart the tender apples, then stir everything together.
Serve warm, adding milk or cream to reach your preferred consistency. Top with chopped fresh apple for a little crunch, extra cinnamon or a drizzle of maple syrup, if desired.
Milk or cream, Additional cinnamon, brown sugar or maple syrup, Chopped fresh apple