Cook the oats. Add steel-cut oats, water, and milk to a saucepot. Bring to a boil, watching carefully so the liquid doesn't boil over. As soon as it boils rapidly, reduce the heat and cook for 1-2 minutes. Remove the oats from the heat and stir in vanilla extract and ground cinnamon if you are using it.
Refrigerate the oats. Let the oats cool for a few minutes, then transfer them into two containers or jars with lids. I use small mason jars. Refrigerate the oats for 8 hours or overnight.
Serve. If needed, add a splash of milk to the oats before serving to make them creamier. Top the oats with cherries or berries and chocolate chips. Serve and enjoy.
Notes
For the creamiest texture, stir the oats well before serving and add a splash of milk if they become too thick overnight.
You can add a pinch of salt to make the flavor more intense.
For some sweetness, serve or top the oats with ripe bananas or maple syrup.