• Preheat oven to 350°F (180°C).
• In a bowl, whisk together dry ingredients. Separately, add wet ingredients to a bowl and whisk to combine. Add dry mixture into wet and mix well to integrate.
• Fold in fresh or frozen berries.
• Spray an 8-inch (1.5-qt) round baking dish with cooking spray (or a 9x9-inch pan). Transfer oatmeal mixture into prepared baking dish.
• Bake 40-50 minutes, until lightly browned and crisped on edges. (A knife should come out mostly clean—it can be a bit moist, but it shouldn’t be soggy. If it is, it needs to bake longer.)
• Cool 10 minutes before serving.
• Serve warm in a bowl on its own, or with toppings like yogurt, whipped cream, nut butter—whatever you like!

Storage & Reheating

• Allow dish to cool completely, then cover and refrigerate. Or cut cooled oatmeal bake into portions and store in airtight containers in the fridge.
• Baked oatmeal will last in the fridge for 4-7 days.
• Reheat individual portions in the microwave for 60-90 seconds, until warmed through. Or reheat in the oven at 350°F (180°C): 15-20 minutes for the full casserole, 5-10 minutes for individual portions.
• To freeze, store the entire casserole in a freezer-safe container, or store individual portions in freezer-safe containers or wrapped in plastic.

Meal Prep

• Method 1: Prep and bake the entire casserole, then store as desired.
• Method 2: Mix and store the dry ingredients the night before, and mix and store the wet ingredients in the fridge so they’re ready. Then, the next day, combine the dry & wet ingredients at the time of baking.
• Don’t mix the dry and wet ingredients together and let the batter sit for too long! The oats will soak up too much of the liquid, which can result in mushy baked oats. Wait to combine the dry and wet mixtures until you’re ready to bake.
• For a larger oatmeal casserole that yields 10-12 servings, double the recipe ingredient amounts and bake in a 9x13-inch dish for 10-15 minutes longer.