Overnight Baked Oatmeal
This is a genuinely hands-off breakfast — mix everything the night before, refrigerate, and bake fresh in the morning while you get ready for the day. The overnight rest lets the oats soak up the custard base, so what comes out of the oven has a texture somewhere between oatmeal and a soft baked pudding.
It's also easy to build around whatever fruit you have — berries, diced apple, or a mix all work in the same base recipe.
Table of Contents
Why This Recipe Works
Old-fashioned rolled oats hold their shape and texture through the overnight soak and bake far better than quick oats, which break down and turn mushier. Letting the mixture rest overnight in the fridge gives the oats time to hydrate fully before baking, which is what gives the finished dish its soft, custardy texture rather than a dry or chalky one.
Ingredients
- 2 cups (180g) old-fashioned rolled oats
- ⅓ cup (65g) brown sugar
- 2 teaspoons baking powder
- 1 teaspoon cinnamon
- ½ teaspoon salt
- 2 cups whole milk
- 2 large eggs
- ¼ cup (56g) unsalted butter, melted
- 1 teaspoon vanilla extract
- 1 cup mixed berries or diced apple
📋 Recipe Card
Overnight Baked Oatmeal
- 2 cups (180g) oats
- ⅓ cup (65g) brown sugar
- 2 cups whole milk
- 2 large eggs
- ¼ cup (56g) butter, melted
- 1 cup berries or diced apple
- Combine oats, brown sugar, baking powder, cinnamon, and salt in a greased 9x9-inch dish.
- Whisk milk, eggs, melted butter, and vanilla separately.
- Pour wet mixture over oats and stir. Fold in fruit.
- Cover and refrigerate at least 8 hours or overnight.
- Bake uncovered at 375°F (190°C) for 35-40 minutes until set and golden.
- Cool 5 minutes before serving.
Step-by-Step
Step 1: Mix the Dry Ingredients
Combine the oats, brown sugar, baking powder, cinnamon, and salt directly in a greased 9x9-inch baking dish.
Step 2: Mix the Wet Ingredients
In a separate bowl, whisk together the milk, eggs, melted butter, and vanilla until combined.
Step 3: Combine and Add Fruit
Pour the wet mixture over the oats in the baking dish and stir everything together. Fold in the berries or diced apple.
Step 4: Refrigerate Overnight
Cover the dish tightly and refrigerate for at least 8 hours, or overnight.
Step 5: Bake
The next morning, bake uncovered at 375°F (190°C) for 35 to 40 minutes, until the top is golden and the center is set rather than liquidy.
Step 6: Serve
Let cool for about 5 minutes before serving warm.
Pro Tips
- Use old-fashioned oats, not quick oats: they hold their texture through the soak and bake much better.
- Don't skip the overnight rest: it's what gives the finished dish its custardy texture.
- Check the center for doneness: the edges typically set before the middle does.
- Serve with a splash of milk or cream: it loosens the texture slightly and adds richness.
Storage & Make-Ahead
This recipe is designed to be made ahead. Once baked, store leftovers covered in the fridge for up to 5 days. Reheat individual portions in the microwave for about 30-45 seconds, or warm the whole dish in a 300°F oven for 10-15 minutes.
Variations & Substitutions
- Banana version: mash 1 ripe banana into the wet mixture and top with banana slices before baking.
- Nutty topping: sprinkle chopped walnuts or pecans over the top before baking for crunch.
- Chocolate chip version: fold in ¼ cup mini chocolate chips along with or instead of the fruit.
- Pumpkin spice: add ¼ cup pumpkin puree and swap cinnamon for pumpkin pie spice.
FAQ
Final Thoughts
This has become a regular in our weekly meal prep since it genuinely needs no morning effort beyond turning on the oven. It reheats well too, which makes it practical for busy weekdays, not just lazy weekends.