Blueberry Crumble With Oats (Melted Butter!)

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This Blueberry Crumble, also known as Crisp, is the one dessert I can simply never get enough of. Fresh blueberries are mixed with a squeeze of lemon juice and cornstarch, with no added sugar so their natural sweet and tart flavor can shine. They’re topped with a simple crumble made with flour, rolled oats, sugar and melted butter – no cold butter, no rubbing! Once baked, this crumble has the perfect ratio of jammy blueberries to crispy, buttery topping. It requires only 10 minutes of easy work, and is unbelievably warm and comforting – whether eaten on its own or with vanilla ice cream.

A baking dish of blueberry crisp with a golden oat topping sits beside two bowls filled with the dessert, one topped with a scoop of vanilla ice cream. A gold spoon rests in the dish; fresh berries are scattered nearby.

3 quick steps

This recipe needs only 3 quick steps that take 10 minutes of work before the crumble is ready to go in the oven:

  1. Toss the blueberries with cornstarch, lemon juice and a pinch of salt. There’s no need to add sugar here as we want the natural sweet and tart flavor of the blueberries to come through. I like to do this step directly in my baking dish to reduce the number of dirty dishes
  2. Make the crumble with melted butter. Simply mix together the flour, rolled oats, sugar, salt and cinnamon with melted butter and you’re good to go!
  3. Assemble. Now add the crumble mixture on top of the blueberries – I recommend placing it in chunks using your hands, and letting some blueberries peek through

That’s it! Now you’re ready to bake. Also – if you’re a fan of peanut butter, this crumble tastes amazing with a peanut butter oat topping, like the one in my apple peanut butter crisp!

A metal dessert dish filled with blueberry crumble, topped with a scoop of vanilla ice cream. A spoon rests in the dish, and more cobbler can be seen in the background.

Why melted butter works in this recipe

The technically “correct” way of making a crumble is to rub cold butter into dry ingredients. This is to ensure the butter stays in chunks so you end up with a craggly, crispy texture. However, after a bit of experimentation, I’ve found melted butter can give you the same results while cutting the work significantly. You just need to remember 2 things:

  1. Don’t overmix. Use a light hand to mix the crumble ingredients until they just come together. Any further handling will start to develop gluten, which we don’t want
  2. Disperse unevenly. When adding the crumble mixture on top of your blueberries, use your fingers to break it into little, uneven chunks. A rough look is best here, as that creates more surface area, and more surface area = crispier crumble!
A close-up of a blueberry crumble in a white dish with a golden serving spoon, showing the dark berry filling and crumbly oat topping. A fresh blackberry sits on the countertop nearby.

Step by step photos

Let’s quickly go over the steps with photos to help you visualize everything:

A white pie dish filled with blueberries coated in cornstarch sits on a wooden surface.
Mix together the blueberry filling ingredients directly in the buttered baking dish.
A glass bowl on a wooden surface filled with oats, sugar, cinnamon, and other baking ingredients, ready to be mixed.
Add the melted butter and dry ingredients for the crumble to a bowl.
A glass bowl filled with oatmeal crumble dough and a metal spoon, placed on a wooden countertop with a checkered pattern.
Use a spoon to mix the ingredients until just combined. The mixture should resemble a crumbly dough.
A round white pie dish filled with blueberry crisp, topped with a golden oat crumble, sits on a wooden surface. The blueberries and oat topping are visible before baking.
Spread the crumble unevenly on top of the blueberries using your hands.

Bake until the crumble is golden and crispy and the blueberries are jammy and bubbly. Serve warm with an optional scoop of vanilla ice cream, and enjoy!

A close-up of a blueberry crumble in a white pie dish, with a golden-brown oat topping and a serving spoon in the dish.

Try it with other fruits, too!

The beauty of this crumble is that the recipe works with so many different types of fruit! You can add in other berries, just like I do in my Mixed Berry Crisp, or even finely chopped apples or peaches. You can also turn it into an Easy Peach Crumble when peaches are in season.

A metal dessert dish filled with a blueberry crumble topped with golden oat topping, beside scattered blackberries and a baking dish on a light countertop.
Print
A baked blueberry crisp in a white dish with a golden oat topping and a portion scooped out, revealing the juicy, purple blackberry filling. A gold serving spoon rests in the dish.

Blueberry Crumble With Oats (Melted Butter!)

by Zoha Malik

5 Stars 4 Stars 3 Stars 2 Stars 1 Star 5 stars from 9 reviews

Jammy blueberries (no added sugar) topped with a crispy oat topping made with melted butter. Only 10 minutes of work needed!

Yield:8 servings

Prep Time:
10 mins
Cook Time:
40 mins
Total Time:
50 mins

Ingredients

Blueberry filling:

  • 4 cups of fresh blueberries, washed and dried (~650g) – can be swapped with frozen; see notes
  • 2 tbsp cornstarch
  • 1 tbsp lemon juice
  • Small pinch of salt

Oat crumble topping:

  • 2/3 cup flour (86g)
  • 2/3 cup old-fashioned rolled oats (80g)
  • 1/2 cup granulated sugar (100g)
  • ½ teaspoon cinnamon, optional
  • ½ tsp salt
  • ½ cup unsalted butter, melted (113g)

Instructions

  1. Preheat your oven to 375F and lightly brush a 9″ pie dish with butter
  2. Add the washed and dried blueberries, cornstarch, lemon juice and salt directly to the pie dish. Toss with a spoon or your hands to combine
  3. Add all the ingredients for the crumble topping to a bowl. Use a large spoon and gently mix until the ingredients are just combined. The result should be a thick, crumbly mixture slightly softer than pie dough. Do not over-mix
  4. Use your fingers to disperse the crumble topping on top of the blueberries, placing it in chunks of varying sizes. Keeping the crumble layer uneven helps ensure it is very crispy after baking. Let some blueberries peek through!
  5. Bake for 40-45 minutes, until the crumble is golden and crispy, and the blueberries are jammy and bubbly
  6. Serve warm on its own or with vanilla ice cream. You can also use plain whipped cream if you want the texture contrast without added sweetness

Video Tutorial

Notes

  • Fresh vs frozen blueberries: You can easily swap the fresh blueberries with frozen. Just make sure the blueberries are fully frozen when you toss them with the other ingredients (don’t let them thaw first)
  • Rolled vs instant oats: I recommend 0ld fashioned rolls oats for the best texture, but if you only have instant oats, you can use them, too
  • Baking dish: I recommend baking this crumble in a 9″ ceramic / glass pie dish. This ensures both layers have the ideal thickness, and the ceramic heats up more slowly than metal, allowing the blueberries to become jammy. However, you may use any ceramic/glass dish of comparable size
  • Make ahead and storage: You can assemble this blueberry crumble ahead of time and keep it covered in the fridge for 1 day (any longer and you risk the berries turning moldy). After baking, keep it at room temperature for up to 1 day, or in the fridge for up to 3 days. Reheat in the microwave to serve.

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Comments

  1. Sara

    Another great recipe from Zoha. Literally made it in 15 minutes for a post-dinner dessert!

    1. Zoha Malik

      WOO! Thank you for trying it – it’s a fave for sure!

  2. Susan

    This is the best! I’ve made one a week for the past 5 or 6 weeks. I mostly used blackberries because they were in season and so delicious. I’ve also made it once with blueberries. Now that peaches are in season, I’ll be making that next. I always add pecans because I think many desserts need them! Using the melted butter works great. This is such a great and easy dessert to make!

    1. Zoha Malik

      I am so glad you’ve enjoyed this crumble in so many ways, Susan! I totally agree, a really easy, delicious and versatile dessert. I love a peach crumble too!

  3. Gina

    I was tempted to add sugar to my blueberries and am so glad I didn’t – this is perfect! I like it served warm with a dollop of Greek yogurt – also unsweetened.

    1. Zoha Malik

      I am glad you trusted the recipe! The tartness from the blueberries is so nice next to the crumble 🙂

  4. Zulekha Haider

    fresh or frozen what so u suggest?

    1. Zoha Malik

      Right now, fresh!

  5. Aashna Shah

    I tried this recipe and everyone loved it! It was a huge hit! My husband wants me to make it again soon. If I want to make 4 portions, do I just halve the recipe? Thank you so much!

    1. Zoha Malik

      Hi Aashna, it’s quite a crowd pleaser, isn’t it!? 🙂 Yes, you can halve the quantities and bake in a smaller dish / pan

  6. Melodee

    This recipe is terrific!!!! It’s easy and delicious!!! 🥰

    1. Zoha Malik

      Woo thank you so much!

  7. Aleena

    Tried it yesterday and it was DELICIOUS!! not overly sweet and everything was perfectly balanced. Everyone absolutely loved it!

    1. Zoha Malik

      YAY I completely agree! it’s so balanced

  8. Saadia

    I have already made it twice. this is how freaking good it is. yummmmmmelicious. thanks ❤️ Zoha for this incredibly simple and delicious recipe. x

    1. Zoha Malik

      WOOO So happy to hear that!

  9. Shanza

    Just made this today and I was drooling from how incredible my kitchen smelled as it baked. The top was perfectly buttery and crisp while the blueberry filling had that perfect jamminess and tartness. It was the ultimate comfort dessert and was super easy to follow too!

    1. Zoha Malik

      AHH that’s exactly how I’d describe this crumble! It is truly just heavenly.

  10. Alia

    Yum yum YUM. It’s so easy and so tasty. The melted butter hack is actually genius.

    1. Zoha Malik

      YAYYYY!

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