9x13 Baked Oatmeal Recipe for Easy, Healthy Breakfasts

Baked oatmeal in a 9×13-inch pan is a simple, wholesome breakfast that combines hearty oats with milk, eggs, and natural sweeteners to create a comforting, sliceable dish. It works well for meal prep since it feeds a crowd and can be customized with your favorite fruits, nuts, or spices. This recipe strikes the perfect balance between creamy and chewy textures, making it a satisfying start to any day.

Ingredients

3 cups old-fashioned rolled oats
2 teaspoons baking powder
1 teaspoon ground cinnamon
1/2 teaspoon salt
2 large eggs
2 1/2 cups milk (dairy or plant-based)
1/2 cup maple syrup or honey
1/4 cup melted coconut oil or unsalted butter
2 teaspoons vanilla extract
1 1/2 cups fresh or frozen berries (blueberries, raspberries, or strawberries)
1/2 cup chopped nuts (walnuts, pecans, or almonds), optional

Instructions

Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish or line it with parchment paper for easier cleanup.

In a large bowl, combine the rolled oats, baking powder, ground cinnamon, and salt. Stir well to distribute the dry ingredients evenly.
In a separate medium bowl, whisk together the eggs, milk, maple syrup (or honey), melted coconut oil (or butter), and vanilla extract until fully combined.
Pour the wet ingredients into the dry oat mixture and stir until the oats are evenly coated. Let the mixture sit for 5 minutes to allow the oats to absorb some liquid.

Gently fold in the fresh or frozen berries and chopped nuts if using, distributing them evenly throughout the batter.
Transfer the mixture to the prepared 9×13-inch baking dish and spread it out evenly with a spatula.
Bake in the preheated oven for 35-40 minutes, or until the top is golden brown and the baked oatmeal is set (a toothpick inserted into the center should come out mostly clean with a few moist crumbs).

Remove from the oven and let cool for 10-15 minutes before slicing into squares. Serve warm or at room temperature.

Tips

Substitutions: Use steel-cut oats for a chewier texture but increase the baking time by 10-15 minutes and add a splash more milk. For a gluten-free version, ensure your oats are certified gluten-free.
Sweeteners: Adjust the sweetness to your taste by using less maple syrup or swapping it for brown sugar, agave, or mashed ripe banana for natural sweetness.

Storage: Store baked oatmeal covered in the refrigerator for up to 5 days. It can also be frozen in airtight containers or wrapped tightly for up to 3 months.
Common mistakes: Avoid overbaking, which can dry out the oatmeal. Start checking for doneness at 30 minutes to ensure moistness, especially if using fresh berries.

Serving Suggestions

Baked oatmeal is delicious on its own or topped with a dollop of Greek yogurt, a drizzle of extra maple syrup, or a splash of warm milk. You can also add fresh fruit slices, a spoonful of nut butter, or a sprinkle of toasted coconut flakes for extra flavor and texture. It pairs beautifully with a hot cup of coffee or tea for a cozy morning meal.

Variations

This recipe is highly versatile. For a chocolate twist, add 1/4 cup cocoa powder to the dry ingredients and fold in mini chocolate chips along with the berries. To make it tropical, swap berries for diced mango and pineapple, and add shredded coconut. For a savory version, omit the sweetener and cinnamon, add chopped herbs, cooked bacon or sausage, and shredded cheese, then bake as directed.

Storage and Reheating

Store leftover baked oatmeal in an airtight container in the refrigerator for up to 5 days. To freeze, wrap individual slices tightly in plastic wrap and place in a freezer-safe bag or container for up to 3 months. Reheat refrigerated portions in the microwave for 45-60 seconds or until warmed through. Frozen portions can be thawed overnight in the fridge and reheated similarly. Alternatively, reheat slices in a 350°F (175°C) oven for 10-15 minutes wrapped in foil to retain moisture.

Frequently Asked Questions

Can I use quick oats instead of rolled oats?
Quick oats will work but may result in a softer, less textured bake. Rolled oats retain a better chew and structure in baked oatmeal, so they’re preferred for this recipe.

Is baked oatmeal healthy?
Yes, baked oatmeal is a nutritious breakfast packed with fiber, complex carbohydrates, and protein when made with wholesome ingredients. You can control added sugars and fats by adjusting sweeteners and oils.

Can I make this vegan?
Absolutely. Replace the eggs with flax eggs (1 tablespoon ground flaxseed + 3 tablespoons water per egg) and use plant-based milk and coconut oil or vegan butter. The texture may be slightly different but still delicious.

How can I add more protein?
Consider adding a scoop of protein powder to the dry ingredients or stirring in Greek yogurt or nut butter before baking. You can also top servings with additional nuts or seeds.

What if I don’t have a 9×13 pan?
You can use a slightly smaller or larger pan, but adjust baking time accordingly. A deeper pan may require longer baking, while a shallower pan may bake faster. Keep an eye on doneness by testing with a toothpick.

Can I prepare baked oatmeal ahead of time?
Yes, you can assemble the mixture the night before, cover it, and refrigerate. Bake fresh in the morning for a warm breakfast. Alternatively, bake it in advance and simply reheat portions as needed.

With this 9×13 baked oatmeal recipe, you have a flexible, crowd-pleasing breakfast or snack that’s easy to prepare and customize. It’s perfect for busy mornings, meal prepping, or feeding a family with minimal fuss and maximum flavor.

9×13 Baked Oatmeal Recipe for Easy, Healthy Breakfasts