In a mixing bowl, add steel cut oats, butter sliced into 1 tablespoon slices, cinnamon, nutmeg, light brown sugar, and salt.
Set aside the bowl to let the butter soften in the bowl before mixing.
Cut up the apples into small 1/2 inch pieces excluding the core and seeds.
In the Instant Pot, add the rest of the butter, lemon juice, vanilla extract, light brown sugar, the rest of the cinnamon, nutmeg, and salt.
Set the instant pot to saute for 2 minutes and stir to combine.
Once the butter is melted, shut off the saute mode and add apples.
Toss the apple to coat with butter and spices
Then, pour in water.
Mix the crumble ingredients together roughly with a large fork.
Next, sprinkle crumb topping evenly over the apples.
Set the pressure cooker to high pressure with the manual setting for 1 minute.
Then, quick release the pressure when the instant pot beeps.