Combine oats with nondairy milk (use 2/3 cup if you like your müesli a little soupy, which I prefer). Chill overnight, or for at least 2 hours. It gets thick, almost like yogurt. Stir in diced fresh fruit such as apple, pear, peach, banana, grapes, or strawberries before serving and enjoy.
Chef's Note: While oats themselves are gluten-free, many brands are cross-contaminated. For a truly gluten-free option, use certified gluten-free oats.