Make Ahead Blueberry Baked Oatmeal

Oatmeal is one of the most comforting breakfasts, whether served warm or prepared the night before. Years ago I developed a blueberry overnight oats variation that inspired this baked version. Unlike some baked oat recipes that can turn out dense or dry, these oats soften overnight in milk, then rise into a tender, cakey texture when baked.

The streusel adds a buttery, slightly crunchy finish, while the blueberries release bursts of sweet-tart flavor as they warm. Assemble the oats the evening before to streamline your morning—and enjoy a delicious, wholesome breakfast all week long.

Why you’ll love this recipe:

• Wholesome and fluffy baked oats, studded with juicy blueberries and finished with a golden streusel.
• Prepped entirely the night before for a convenient meal-prep breakfast or brunch.
• Flexible and easy to customize—simple swaps make it vegan or gluten-free.

Recipe ingredients

If you need to swap an ingredient, use common pantry substitutes such as oat flour for all-purpose flour, or a flax egg in place of a whole egg to make this vegan.

Ingredient notes

• Oats: Use old-fashioned rolled oats for the best texture in this recipe.
• Milk: Any dairy or non-dairy milk works; choose based on flavor preference and dietary needs.
• Sweetener: Maple syrup, honey, or another favorite sweetener may be used in both the oat base and the streusel.
• Egg: For a vegan option, replace the egg with a flax egg or preferred egg replacer.
• Blueberries: Fresh or frozen blueberries are fine; if using frozen, thaw briefly and pat dry to avoid excess liquid.
• Flour: Substitute all-purpose flour with oat flour, almond flour, or a gluten-free 1:1 blend to make the streusel gluten-free.
• Coconut oil: Melted coconut oil creates a tender streusel; melted butter can be used instead for a richer flavor.

How to make blueberry baked oats

This recipe has two components: the overnight oat base and the streusel topping. Preparing the oats the night before lets them absorb the liquid and soften, resulting in a lighter baked texture. The streusel can be mixed ahead and refrigerated for a few days, or omitted if you prefer a simpler finish.

1. Evening: In a medium bowl, combine 2 cups old-fashioned rolled oats, 2 cups unsweetened almond milk (or milk of choice), 1/3 cup pure maple syrup (or preferred sweetener), and 2 teaspoons ground cinnamon. Stir, cover, and refrigerate overnight. (Do not add the egg or baking powder yet.)
2. Morning: Preheat oven to 375°F (190°C) and grease an 8×8-inch baking dish.
3. Stir a beaten large egg and 1 teaspoon baking powder into the chilled oat mixture until fully combined, then gently fold in 1½ cups fresh or thawed blueberries. Spread the mixture evenly in the prepared dish.
4. Prepare the streusel: In a medium bowl, mix 1 cup rolled oats, 1/2 cup all-purpose flour (or substitute), 1/2 cup packed brown sugar, and 1/4 teaspoon salt. Stir in 1/2 cup melted coconut oil (or melted butter) until crumbly. Sprinkle evenly over the oat layer.
5. Bake on the middle rack for 30–40 minutes, until most of the liquid has been absorbed and the top is golden. If the streusel browns too quickly, loosely tent with foil for the remaining time.
6. Remove from the oven and cool on a rack for 10–15 minutes before serving. Enjoy warm or at room temperature.

Recipe FAQs

Recipe notes

• Pro tip: Make the streusel up to a few days ahead and keep it refrigerated in an airtight container. It can also be left off if you prefer a simpler texture.
• Leftovers: Refrigerate for up to 5 days or freeze for up to 3 months.
• Vegan option: Use a flax egg or other egg replacement in place of the egg.
• Customization: Swap milk, sweetener, fruit, or spices to suit your tastes. Oat flour or almond meal work well for a gluten-free streusel.