In a Tupperware container or jar, mix steel-cut oats with milk. Add chia seeds if desired and mix well. The chia seed will float to the top and that’s okay. Refrigerate overnight or at least 4 hours. In the morning, mix chia seeds in with a spoon. If the oatmeal is too dry for your liking, add an extra spash of milk. Top with fresh berries or fruit, dried fruit, chopped nuts, or nut butter, and enjoy.