Pretty much this. It's not so much "cooking oatmeal and protein together". It's adding protein powder to already-cooked oats.
I generally boil water, toss steel cut oats in a bowl, then add the water, cover it for 5 minutes or so. Then add Metabolic Drive and extra water if needed (I prefer oatmeal on the thicker side instead of thinned out), and last, add extras like cinnamon, peanut butter, blueberries, almonds, or whatever.
A night-before breakfast I'll make sometimes is equal parts steel cut oats, milk, and Greek yogurt (usually 4-6 tablespoons each) and a handful of frozen fruit all in a covered bowl, let sit in the fridge overnight. Next morning, stir in a scoop of protein and some extra milk (or even water), and you're good to go.