You are probably wondering if you can make overnight oats with steel-cut oats! Steel-cut oats contain the outer layer of the oat kernel, and they won't soak and swell as much. The result won't be as smooth and creamy, and they will stay slightly hard, so I don't recommend this option. The best is to use old-fashioned oats. You can use certified gluten-free oats if you have gluten sensitivities. Quick oats are great for baby overnight recipes.