Baked Oatmeal Recipe With Blueberries, Banana and Walnuts

Baked oatmeal is what happens when overnight oats meet a muffin. You stir oats, milk, eggs, banana and fruit together in one bowl, pour it into a dish and bake it for about 40 minutes. What comes out is soft and custardy in the middle, golden at the edges, and firm enough to cut into squares you can reheat all week.

This baked oatmeal recipe is the one I keep coming back to: blueberries and banana for sweetness, walnuts for crunch, and only 3 tablespoons of maple syrup for the whole pan. It makes 6 squares at about 289 calories and 9 g protein each. Below the recipe you’ll find apple cinnamon, pumpkin and peanut butter versions, plus how to store and reheat it.

Baked Oatmeal Ingredients

Makes: 6 squares (one 8×8-inch dish)  |  Prep: 10 minutes  |  Bake: 35 to 40 minutes

• 2 cups (160 g) old-fashioned rolled oats
• 1 tsp baking powder
• 1 1/2 tsp ground cinnamon
• 1/4 tsp salt
• 1 medium ripe banana (about 118 g), mashed
• 1 1/2 cups (366 g) 2% milk
• 2 large eggs
• 3 tbsp (60 g) maple syrup
• 2 tbsp (28 g) butter, melted
• 1 tsp vanilla extract
• 1 cup (148 g) blueberries, fresh or frozen
• 1/3 cup (39 g) chopped walnuts

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How to Make Baked Oatmeal

1. Heat the oven to 375°F and grease an 8×8-inch baking dish.
2. In a large bowl, mix the oats, baking powder, cinnamon and salt.
3. In a second bowl, mash the banana, then whisk in the milk, eggs, maple syrup, melted butter and vanilla.
4. Pour the wet mixture over the oats and stir. Fold in most of the blueberries and walnuts.
5. Spread it in the dish and scatter the rest of the blueberries and walnuts on top.
6. Bake 35 to 40 minutes, until the center is set and the edges are golden.
7. Let it rest 10 minutes, then cut into 6 squares.

Per square (1/6 of the pan): about 289 calories, 9 g protein, 37 g carbs, 13 g fat and 4 g fiber. Skip the walnuts and it drops to about 246 calories and 8 g protein. I calculated these from USDA FoodData Central values for each ingredient. Baking powder, cinnamon, salt and vanilla are left out because they add next to nothing.

Tips for Baked Oatmeal That Isn’t Dry or Gummy

Most bad baked oatmeal is either dry and crumbly or wet in the middle. Both are easy to avoid.

• Use old-fashioned rolled oats. Quick oats soak up the milk too fast and bake into a dense, pasty slab. Steel-cut oats stay hard in this bake time. Rolled oats keep some chew while the rest turns creamy.
• Don’t cut back the milk. The batter will look soupy when it goes in the oven. That’s right. The oats need all of that liquid to soften as they bake.
• Use a really ripe banana. Brown spots mean more sweetness, so you can keep the maple syrup low without the pan tasting flat.
• Judge by the center, not the clock. Give the dish a gentle shake. If the middle still wobbles like liquid, give it 5 more minutes. A slight jiggle is fine because it firms up as it rests.
• Frozen blueberries go in straight from the freezer. Thawed berries bleed purple through the whole pan. Add 3 to 5 minutes to the bake time.

Want it ready faster in the morning? Stir everything together the night before, cover the dish and refrigerate it, then bake in the morning. The oats soak overnight, much like overnight oats recipes, so the texture comes out even softer. Give it a few extra minutes in the oven since it starts cold.

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Baked Oatmeal Variations

Keep the same oats, milk, eggs and leaveners, and change only the fruit and flavor. Calories shift with each swap, so the numbers above apply only to the blueberry version.

Apple Cinnamon Baked Oatmeal

Swap the blueberries for 1 large apple, cored and diced (no need to peel). Go up to 2 tsp cinnamon and add a pinch of nutmeg. Pecans work better than walnuts here. This is the version I make most in October.

Pumpkin Baked Oatmeal

Replace the banana with 3/4 cup canned pumpkin purée (not pumpkin pie filling) and add 1 1/2 tsp pumpkin pie spice. Leave out the blueberries and fold in a handful of chopped pecans or a few dark chocolate chips. Pumpkin isn’t as sweet as banana, so taste the batter and add 1 more tablespoon of maple syrup if you like. If you’re working through a can, the leftovers fit right into healthy pumpkin muffins.

Peanut Butter Banana Baked Oatmeal

Swap the melted butter for 1/4 cup creamy peanut butter whisked into the wet ingredients. Use 2 bananas, skip the blueberries and top with banana slices before baking.

Mixed Berry Baked Oatmeal

Use any mix of raspberries, chopped strawberries and blueberries, 1 cup total. Add the zest of half a lemon to the wet ingredients. The lemon makes the berries taste brighter.

Healthy Swaps and More Protein

• Dairy-free: use unsweetened soy or oat milk and swap the butter for coconut oil or a mild olive oil.
• Egg-free: replace the 2 eggs with 2 flax eggs (2 tbsp ground flaxseed plus 5 tbsp water, rested 5 minutes). The squares will be softer and a little crumblier.
• Less sugar: drop the maple syrup to 1 tablespoon and use 2 very ripe bananas.
• More protein: serve each square with a scoop of plain Greek yogurt, or eat it alongside eggs. If you want more of the protein baked in, our protein overnight oats recipe shows how to work whey into oats without a chalky taste.

How to Store and Reheat Baked Oatmeal

Baked oatmeal is a casserole with eggs, and the FoodSafety.gov cold storage chart gives casseroles with eggs 3 to 4 days in the refrigerator after baking and 2 to 3 months in the freezer. That makes one pan a natural fit for weekday breakfasts.

You’ll also loveMason Jar Salads That Stay Crisp Until Thursday

• Fridge: cool completely, then cover the dish or move the squares to an airtight container. Eat within 4 days.
• Freezer: wrap each square in plastic wrap, then put them all in a freezer bag. Pull one out the night before and let it thaw in the fridge.
• Reheat: microwave a square for 45 to 60 seconds with a splash of milk on top so it doesn’t dry out. It’s also good cold, straight from the container.

If you prep breakfast on Sundays, one pan of this plus a batch of egg muffins covers the whole week. More make-ahead options are in our breakfast meal prep ideas.

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Baked Oatmeal vs Overnight Oats

They start from almost the same ingredients, but they suit different mornings. Overnight oats are no-cook, eaten cold from a jar, and take 5 minutes to put together. Baked oatmeal takes an hour start to finish, but you get a warm breakfast that slices like cake and feeds six people from one dish. In the summer I lean on jars. Once it’s cold out, I switch to the pan. If oats are on your plate most days, here’s what eating oatmeal every day does.

Baked Oatmeal FAQ

Can I make baked oatmeal without eggs?

Yes. Use 2 flax eggs as described above. The eggs are what make the squares hold together, so the egg-free version is softer and works better scooped into a bowl than cut into bars.

Why is my baked oatmeal soggy in the middle?

Usually it needs more time, or the dish was too small and the layer too deep. In a 9×9-inch dish it bakes a little faster. In a smaller or deeper dish, add 5 to 10 minutes and check that the center no longer looks wet.

Can I double the recipe?

Yes. Double everything and bake it in a 9×13-inch dish. Start checking at 40 minutes. Thicker pans can take up to 50.

Sources

• USDA FoodData Central nutrient values per 100 g: oats, regular and quick, dry (FDC 173904); milk, reduced fat 2% (FDC 2705386); egg, whole, raw (FDC 171287); bananas, raw (FDC 173944); maple syrup (FDC 169661); butter, salted (FDC 173410); blueberries, raw (FDC 171711); walnuts, English (FDC 170187). Accessed via FoodData Central and GetFoodFacts, which cites the FDC IDs.
• FoodSafety.gov, Cold Food Storage Chart.