Rinse oat groats. There's no need to soak the groats.
Combine groats, milk, and water in the Instant Pot. Stir in optional spices (to taste). Stir to combine and close the lid.
Pressure cook on High Pressure for 30 minutes. [See Note 2]
Once pressure cooking is complete, allow the Instant Pot to do a natural pressure release (NPR) or a 15-minute natural release if you're short on time. Open the lid. [Read More: The Different Pressure Release Methods]
Open the Instant Pot and stir the oat groats and serve into individual bowls, topping with your choice of toppings.
Notes
Note 1: Use any combination of milk and water. You can also omit the milk and use water only.
Note 2: For al dente or chewier groats, decrease the pressure cooking time to 20 minutes. For softer groats, increase pressure cooking time to 40 minutes.
Note 3: For a drier version to use in grain bowls or as a substitute for rice, use a ratio of 1:1.75 of groats to liquid. Use only water, and omit the milk.
Note 4: This recipe can be doubled as long as you don't go past the ½ full mark of your Instant Pot liner (inner pot).