By Karyl Leavings. Updated November 26, 2025.
This ultra-cozy Overnight Apple Crisp Casserole is the make-ahead breakfast bake your fall mornings have been waiting for. Juicy cinnamon apples melt into a golden, buttery oat crisp that bakes to bubbly perfection all while you sleep. Just assemble, refrigerate, and wake up to the sweetest aroma filling your kitchen.
Table of Contents
Overnight Apple Crisp Casserole
- Total Time: 1 hour 10 minutes
- Yield: 8 servings 1x
Description
A cozy make-ahead Overnight Apple Crisp Casserole with tender cinnamon apples and a golden oat crumble topping you assemble the night before and bake fresh in the morning.
Ingredients
6–8 medium apples (900–1100 g), peeled, cored, and diced
1/2 cup (100 g) packed light brown sugar, divided
1/4 cup (50 g) granulated sugar
1–2 teaspoons ground cinnamon
1/4 teaspoon ground nutmeg (optional)
1–2 tablespoons (15–30 ml) lemon juice or apple cider vinegar
1 teaspoon (5 ml) vanilla extract
1 cup (90 g) old-fashioned rolled oats
1 cup (120 g) all-purpose flour
1/4 teaspoon fine sea salt
1/2 cup (113 g) unsalted butter, melted (or plant-based butter)
1/2 cup (60 g) chopped pecans or walnuts (optional)
Instructions
1. Grease a 9×13-inch (23×33 cm) baking dish with butter or nonstick spray.
2. In a large bowl, combine the diced apples, granulated sugar, half of the brown sugar, cinnamon, nutmeg (if using), lemon juice, and vanilla. Toss until all of the apples are evenly coated.
3. Spread the apple mixture evenly in the prepared baking dish, making sure the apples are in a level layer.
4. In a separate bowl, stir together the rolled oats, flour, remaining brown sugar, and salt. Pour in the melted butter and mix until the topping looks like damp, clumpy sand with some larger crumbles.
5. Sprinkle the oat mixture evenly over the apples, covering them from edge to edge without pressing the topping down.
6. Cover the baking dish tightly with plastic wrap or foil and refrigerate for at least 8 hours or up to 24 hours.
7. When ready to bake, preheat the oven to 350°F (177°C). Remove the casserole from the fridge while the oven heats.
8. Uncover the casserole and bake for 45–55 minutes, or until the apples are tender, the edges are bubbly, and the topping is deep golden brown.
9. Let the casserole cool for 10–15 minutes so the juices thicken slightly, then serve warm with yogurt, whipped cream, or vanilla ice cream if desired.
Notes
Use a mix of sweet and tart apples, such as Honeycrisp and Granny Smith, for the best flavor and texture.
For a gluten-free version, use certified gluten-free oats and replace the all-purpose flour with a 1:1 gluten-free flour blend or oat flour.
To make the casserole dairy-free, swap the butter for melted coconut oil or your favorite plant-based butter.
If you like extra crunch, stir chopped pecans or walnuts into the oat topping before baking.
Leftovers keep well in the refrigerator for up to 4 days. Reheat individual servings in the microwave or warm the whole pan at 325°F (163°C) for 15–20 minutes.
- Prep Time: 20 minutes
- Cook Time: 50 minutes
- Category: Breakfast & Brunch
- Method: Baked
- Cuisine: American
Nutrition
- Serving Size: 1 slice
- Calories: 285
- Sugar: 29
- Sodium: 120
- Fat: 10
- Saturated Fat: 6
- Unsaturated Fat: 3
- Trans Fat: 0
- Carbohydrates: 48
- Fiber: 4
- Protein: 3
- Cholesterol: 25
About This Recipe
This recipe transforms classic apple crisp into a no-stress, overnight-friendly casserole perfect for breakfast, brunch, or dessert. Letting the apples sit overnight draws out their juices, creating a naturally rich, caramel-style sauce that bubbles through the oat topping while it bakes. The result is a warm, fragrant, golden apple crisp with minimal morning prep.
Why it works:
The overnight rest softens the apples, deepens the spice flavor, and ensures the crisp topping bakes evenly-no soggy spots, no undercooked centers.
When to make it:
Holiday mornings, lazy Sundays, potluck brunches, meal prep breakfasts, or any time you want a make-ahead dish that feels extra special.
Why You’ll Love It
- Make-ahead magic: Everything is assembled the night before zero morning stress.
- Perfectly tender apples: The overnight soak creates a naturally syrupy sauce.
- Golden, crunchy topping: Bakes crisp every time, never mushy.
- Crowd-friendly casserole size: Ideal for gatherings or meal prep.
- Cozy flavors: Cinnamon, vanilla, and warm brown sugar in every bite.
Apples (900–1100g / about 6–8 medium)
Choose firm, crisp varieties such as Honeycrisp, Granny Smith, Pink Lady, or Fuji. Mixing sweet and tart apples gives the casserole a deeper, more layered flavor.
Swap: Pears, or a mix of pears and apples for a softer, sweeter bake.
Brown Sugar (100–150g / ½–¾ cup)
Adds warm molasses sweetness and helps create that caramel-like sauce.
Swap: Coconut sugar for a less refined alternative.
Rolled Oats (90g / 1 cup)
Use old-fashioned rolled oats for the best texture. Quick oats get mushy; steel-cut oats won’t soften enough overnight.
Gluten-free: Choose certified GF oats.
All-Purpose Flour (120g / 1 cup)
Helps bind the topping and add structure.
Swap: Oat flour or a 1:1 gluten-free blend.
Butter (113g / ½ cup)
Provides richness and crispness. If using melted butter, pour it evenly over the topping.
Dairy-free: Use plant-based butter or coconut oil.
Cinnamon & Vanilla
These warm, comforting flavors are classic in apple desserts.
Optional add-ins: Nutmeg, cardamom, or a pinch of clove.
Lemon Juice (15–30ml / 1–2 tbsp)
Brightens the apple flavor and prevents browning.
Swap: Apple cider vinegar.
How to Make Overnight Apple Crisp Casserole
1. Prep the Apples
Peel and slice apples into ¼-inch (0.6 cm) pieces. Toss them with brown sugar, granulated sugar, cinnamon, vanilla, and lemon juice until every slice glistens.
Visual cue: The apples should look lightly coated and shiny.
2. Fill the Casserole Dish
Grease a 9×13-inch (23×33 cm) baking dish, then spread the apples evenly across the bottom.
3. Mix the Crisp Topping
Combine oats, flour, brown sugar, salt, cinnamon, and melted butter. Stir until the mixture resembles damp sand with a few larger clusters.
4. Assemble
Sprinkle the topping evenly over the apples. Don’t pack it down air pockets help create a crisp texture.
5. Refrigerate Overnight
Cover the casserole tightly and chill for 8–24 hours.
6. Bake
Preheat to 350°F (177°C). Bake uncovered for 45–55 minutes, or until the apples are soft, the topping is golden-brown, and the edges are bubbling.
Visual cue: The center should be set, the topping crisp, and the apples fork-tender.
Pro Tips for Success
- Slice apples evenly so they cook at the same rate.
- Don’t skip the lemon juice (or vinegar)-it balances the sweetness.
- Use rolled oats only for that classic crisp texture.
- Bake uncovered so the topping can brown properly.
- Let it cool 10–15 minutes after baking so the juices thicken.
- For extra crispiness, broil for 1–2 minutes at the end, watching closely.
- Add nuts (pecans/walnuts) to the topping for crunch.
Variations & Substitutions
- Gluten-Free: Use oat flour and certified GF oats.
- Dairy-Free: Replace butter with coconut oil or plant-based butter.
- No-Refined Sugar: Sweeten with maple syrup (reduce liquid slightly).
- Maple Cinnamon: Add 2 tbsp (30ml) maple syrup to the apples.
- Caramel Apple: Stir in 2 tbsp (30g) caramel sauce (or use date caramel).
- Berry Apple: Add 1 cup (150g) blueberries or cranberries for color and tang.
Serving & Storage
Refrigeration
Store leftovers in an airtight container for up to 4 days.
Freezing
Freeze the baked casserole for up to 3 months. Thaw overnight in the fridge before reheating.
Reheating
Warm individual servings in the microwave (30–45 seconds) or reheat the whole pan at 325°F (163°C) for 15–20 minutes.
Shelf Life
Best within the first 48 hours when the topping is at peak crunch.
FAQs
How do I prevent the topping from getting soggy?
Bake uncovered so moisture can escape. Using rolled oats and enough butter helps the topping crisp up. Allowing the casserole to rest after baking also keeps it crisp rather than steamy.
Can I prepare this without refrigerating overnight?
Yes! If you’re short on time, assemble and bake immediately. However, the overnight rest enhances flavor and softens the apples for a more tender result.
Which apples are best for apple crisp?
Firm, crisp apples such as Granny Smith, Honeycrisp, Pink Lady, and Fuji hold their shape well. Using a mix adds complexity sweet, tart, and fragrant.
Can I reduce the sugar?
Absolutely. Reduce sugar by up to 30% without affecting texture. The apples will release less syrup, but the flavor remains delicious.
Can I make this in a slow cooker?
Yes. Cook on LOW for 3–4 hours, uncovered for the last 30 minutes to allow the topping to crisp slightly.
Can I double the recipe?
Yes, use two 9×13 pans or one extra-deep casserole. Increase baking time by 10–15 minutes until bubbly.
External Links (High-Authority Sources)
How do I prevent the topping from getting soggy?
Bake uncovered so moisture can escape. Using rolled oats and enough butter helps the topping crisp up. Allowing the casserole to rest after baking also keeps it crisp rather than steamy.
Can I prepare this without refrigerating overnight?
Yes! If you’re short on time, assemble and bake immediately. However, the overnight rest enhances flavor and softens the apples for a more tender result.
Which apples are best for apple crisp?
Firm, crisp apples such as Granny Smith, Honeycrisp, Pink Lady, and Fuji hold their shape well. Using a mix adds complexity sweet, tart, and fragrant.
Can I reduce the sugar?
Absolutely. Reduce sugar by up to 30% without affecting texture. The apples will release less syrup, but the flavor remains delicious.
Can I make this in a slow cooker?
Yes. Cook on LOW for 3–4 hours, uncovered for the last 30 minutes to allow the topping to crisp slightly.
Can I double the recipe?
Yes, use two 9×13 pans or one extra-deep casserole. Increase baking time by 10–15 minutes until bubbly.
Conclusion
This Overnight Apple Crisp Casserole brings together all the flavors we love warm cinnamon, tender apples, and a golden, buttery crumble in the easiest make-ahead bake imaginable. If you tried this recipe, please leave a rating, share your thoughts in the comments, and join our Flavor & Recipes newsletter for more cozy kitchen inspiration!
