Rinse (optional) steel cut oats under cold water, then drain.
Use a ratio of 1 part oats to 4 parts water (for softer oats use 1:5).
Add oats and water (and a pinch of salt, if desired) to a pot.
Bring to a boil over medium-high heat.
Reduce heat to low and maintain a gentle simmer.
Cook uncovered, stirring occasionally, for 20–30 minutes until tender and creamy.
For creamier texture, stir more often during the last 5–10 minutes.
To prevent sticking, keep heat low and stir as needed.
If you want to add milk, reduce water to 3 parts and add 1 part milk during the last 5–10 minutes (or add all milk after simmering).
Sweeten after cooking if desired (honey, maple syrup, brown sugar).
Add flavorings after cooking (vanilla, cinnamon, nutmeg).
Serve immediately, or cool and reheat with a splash of water or milk.
Microwave option: combine 1/4 cup oats with 1 cup water in a microwave-safe bowl; microwave on high 3 minutes, stir, then microwave in 1–2 minute intervals until tender (about 8–12 minutes total).