Select SAUTE on the Instant Pot and adjust to More for high heat.: The pot will hiss and the metal insert will warm quickly, sending out a faint metallic warmth that tells you the surface is hot enough. This step preps the pot to toast the oats slightly, which deepens their flavor. If the pot does not heat, check that it is properly seated and that the lid is open; a cold insert means the sauté setting may not engage properly. You'll want to see a thin shimmer on the surface when the insert is ready.
Add the butter and stir until melted.: You will hear a soft sizzle as the unsalted butter hits the hot base and see it liquefy into a glossy pool, releasing a nutty scent. This melted butter coats the grains and prevents sticking while adding richness. Avoid letting it brown deeply, as that can introduce a toasted bitterness; aim for a steady sheen and gentle bubbling around the edges.
Add the oats and stir to coat them with butter, stirring frequently, about 4 minutes.: When the steel cut oats hit the butter, they will smell toasty and release a warm, rice like aroma. Stirring keeps them toasting evenly, and you'll notice the oats take on a slightly darker hue and a nuttier fragrance. The frequent stirring prevents scorching; if you stop stirring, you risk hot spots that burn the oats and create off flavors.
Add the sugar, salt, water, milk, raisins and cinnamon. Stir until combined.: As you pour in the water and milk , the kitchen will fill with a sweet, spiced steam. The raisins sink then bob up as they begin to hydrate, and the cinnamon lifts the aroma into cozy territory. Stirring distributes the ingredients so everything cooks uniformly. Skipping this mix can lead to pockets of dry oats or uneven seasoning, so make sure you fully combine before sealing the pot.
Secure the lid and set the Pressure Release to SEALING. Press the CANCEL and then select PORRIDGE or MANUAL or PRESSURE COOK (Any of these settings will work). Adjust the pressure to High and set the time to 10 minutes.: You will hear the valve click as it moves to sealing, and the display will show the chosen program. The pot will build pressure and then cook steadily, producing a gentle, humming sound. The high pressure forces liquid into the oats, creating creaminess while preserving structure. A common mistake is not setting the valve to sealing, which prevents pressure buildup and yields undercooked oats, so double check the valve position.
Allow the pressure to release naturally for 5 minutes (don't do anything), then Quick Release any remaining pressure. Carefully remove the lid.: During natural release you will notice the pot settling, and steam will ease off slowly. This short natural release lets the oats finish absorbing liquid gently, improving texture. When you Quick Release, stand back briefly to avoid a hot steam burst. Opening the lid too early can splash hot porridge and disrupt the texture, so take care and lift the lid away from you.
Stir the oatmeal with a large wooden spoon.: As you stir, the porridge will sigh and thicken, giving off a cloud of sweet steam with warm spice notes. A wooden spoon is gentle on the grain structure and helps you feel the final consistency, catching any undercooked bits at the bottom. If the mix seems too stiff, a splash of extra milk will loosen it; conversely, over stirring aggressively can make it glue like, so stir just enough to combine and check texture.
Transfer to bowls and sprinkle on the brown sugar and add extra milk, if desired.: Lifting spoonfuls into warm bowls releases a comforting aroma and reveals pockets of plumped raisins . The brown sugar melts into warm crevices, offering caramel like notes, while an extra splash of milk brightens the mouthfeel. A typical oversight is adding cold milk straight from the fridge to hot porridge, which can cool the bowl too quickly; warm the milk slightly if you prefer a uniform temperature.
Serve at once and enjoy!: The first spoonful should be warm, with a mix of creamy and chewy textures and a gentle cinnamon perfume. Serve promptly to enjoy the intended contrast, because as it sits the porridge firms up. If you need to hold it, keep the pot on the warm setting and stir occasionally to maintain creaminess, but beware that prolonged holding will change texture.