Add the steel cut oats, water, milk, maple syrup, butter, cinnamon, and salt to the Instant Pot. Stir everything together to combine.
Lock the lid and set the valve to sealing. Pressure cook on high for 4 minutes.
When the cook time is complete, allow a natural pressure release for 10 minutes. This step is important because it allows the oats to continue cooking and absorbing liquid, resulting in the perfect creamy texture.
Carefully switch the valve to venting to release any remaining pressure. Remove the lid once the pin drops.
Stir the oats well. They will thicken up as they sit. If you prefer a thinner consistency, stir in a splash of milk.
Divide into bowls and top with fresh berries, a sprinkle of brown sugar, and chopped pecans. Serve warm.