Why You’ll Love This Mixed Berry Chia Seed Crumble

• It’s deceptively simple. You really don’t need any fancy skills or equipment for this one. It’s mostly a matter of mixing a few things in bowls and letting the oven do the rest of the work.
• The chia seeds are a brilliant thickener. Forget cornstarch or flour pastes—the chia seeds swell up with the berry juices, creating a lush, jam-like consistency that’s completely natural and adds a lovely little texture.
• It’s wonderfully adaptable. Have some peaches that need using? Toss them in. Only have frozen blueberries? That works perfectly. This recipe is a fantastic template for whatever fruit you have on hand.
• It feels both indulgent and wholesome. With the oats, nuts, and seeds in the crumble and the burst of fruit underneath, every spoonful is satisfying in a way that a super-rich dessert sometimes isn’t. It’s comfort food that comforts you all the way through.

Ingredients & Tools

• For the Berry Filling:
• 500 g mixed berries (fresh or frozen)
• 3 tbsp chia seeds
• 3 tbsp maple syrup or honey
• 1 tsp vanilla extract
• Zest of 1 lemon
• 1 tbsp lemon juice
• Pinch of sea salt
• For the Crumble Topping:
• 120 g rolled oats (not instant)
• 60 g almond flour
• 40 g chopped walnuts or pecans
• 3 tbsp coconut oil, solid, or cold unsalted butter
• 2 tbsp maple syrup
• 1/2 tsp ground cinnamon
• 1/4 tsp ground nutmeg
• Pinch of sea salt

Tools: An 8×8 inch baking dish (or similar size), two mixing bowls, a whisk or fork.

The beauty of this list is its simplicity. Using almond flour instead of regular flour in the topping keeps it gluten-free and adds a lovely richness, while the coconut oil gives it a fantastic crispness. And honestly, don’t skip the lemon zest—it really brightens up the whole dish and keeps the berries from tasting too flat.

Serves: 6 | Prep Time: 15 minutes | Cook Time: 35-40 minutes | Total Time: 50-55 minutes

Before You Start: Tips & Ingredient Notes

• Frozen vs. Fresh Berries? Honestly, frozen berries work beautifully here and are often more economical. There’s no need to thaw them first—just mix them straight from the freezer. You might find the baking time increases by a minute or two, but that’s it.
• What’s the deal with the chia seeds? They’re not just for pudding! In this filling, they act as a powerful natural thickener. As they sit with the juicy berries, they absorb the liquid and create a gorgeous, glossy gel—no lumps, no fuss.
• Getting the Topping Right. The trick is to have your fat (coconut oil or butter) cold. This is crucial for achieving that desirable crumbly, crisp texture instead of a pasty one. Use your fingers to rub it in until you have a mix of pea-sized crumbs and sandy mixture.
• Sweetener Swaps. Maple syrup gives a lovely, deep flavour, but honey works just as well. If you prefer a less sweet dessert, you can reduce the sweetener in the filling by a tablespoon—taste your berries first to see how tart they are.

How to Make Mixed Berry Chia Seed Crumble

Serving Suggestions

Complementary Dishes

• A scoop of vanilla bean ice cream — The classic pairing for a reason. The cold, creamy ice cream melting into the warm, tart berries is a textural dream come true.
• A dollop of thick Greek yogurt or coconut whipped cream — For a slightly lighter option that still adds a wonderful creaminess and a tangy contrast to the sweet fruit.
• Alongside a simple, sharp cheese plate — An unexpected but fantastic pairing. A few slices of aged cheddar or a crumbly goat cheese served before or with the crumble creates a sophisticated sweet-and-savory experience.

Drinks

• A hot cup of Earl Grey tea — The bergamot in the tea complements the citrus notes in the crumble beautifully, making for a very cozy and elegant dessert pairing.
• A glass of chilled dessert wine, like a Moscato d’Asti — The slight effervescence and sweet peach notes in the wine mirror the fruitiness of the berries and cut through the richness of the topping.
• A simple glass of cold milk — Sometimes, the simple, nostalgic options are the best. It’s refreshing and comforting all at once.

Something Sweet

• A small, rich dark chocolate truffle — After a bowl of crumble, a single piece of intense dark chocolate is the perfect finale, satisfying any lingering chocolate cravings without being too much.
• A drizzle of extra maple syrup — For those who have a serious sweet tooth, a little extra drizzle over the top just before serving adds a beautiful shine and an extra layer of flavour.
• A few fresh mint leaves — Not a dessert, but a garnish that makes all the difference. The fresh, cool aroma of mint makes each bite of the warm crumble feel even more vibrant.

Top Mistakes to Avoid

• Mistake: Using melted fat in the topping. This is probably the number one reason for a soggy or greasy crumble. If your coconut oil or butter is liquid, the topping will just absorb it and become pasty instead of crumbly. It must be solid and cold.
• Mistake: Skipping the resting time for the filling. Those 5-10 minutes you let the berries and chia seeds hang out are not optional! This is when the chia seeds begin to gelatinize. Skipping it can lead to a runny filling.
• Mistake: Pressing the topping down. You want a light, fluffy, and craggy layer that the heat can penetrate easily. If you press it into a compact layer, it will steam rather than bake, resulting in a soft, chewy top instead of a crisp one.
• Mistake: Not letting it cool before serving. I’ve burned my tongue too many times to count! Beyond safety, the cooling time is essential for the filling to set. If you cut into it straight from the oven, it will be soupy.

Expert Tips

• Tip: Make a double batch of the crumble topping and freeze it. Seriously, this is a game-changer for easy desserts. Mix up a big batch of the dry crumble ingredients (oats, almond flour, nuts, spices) and keep it in a freezer bag. When you want a crumble, just take out what you need, rub in the cold fat and syrup, and you’re minutes away from dessert.
• Tip: Add a tablespoon of oat flour to extra-juicy fruit. If you’re using very ripe summer peaches or particularly wet berries, adding a single tablespoon of oat flour or almond flour to the filling mixture can provide an extra insurance policy against a runny result, working alongside the chia seeds.
• Tip: For a super-crispy top, use a mix of fats. Try using half cold butter and half cold coconut oil. The butter adds incredible flavour while the coconut oil gives a fantastic crispness. The combination is truly next-level.
• Tip: Broil for the last minute. If your crumble is baked but you want an even deeper golden colour and extra crunch, pop it under the broiler for just 60-90 seconds. Watch it like a hawk though—it can burn in a flash!

FAQs

Can I make this crumble ahead of time?
Absolutely! You can assemble the entire crumble—filling and topping—cover it tightly, and refrigerate it for up to 24 hours before baking. You might need to add a few extra minutes to the baking time since it will be going into the oven cold. It’s a fantastic option for stress-free entertaining.

How should I store leftovers, and how long do they keep?
Leftovers (if you have any!) can be covered and stored in the refrigerator for up to 3 days. The topping will soften, but it’s still delicious. To re-crisp the topping, reheat individual portions in a toaster oven or a conventional oven at 350°F (175°C) for about 10 minutes. I don’t recommend freezing the assembled baked crumble, as the topping tends to get very soggy upon thawing.

Can I use all-purpose flour instead of almond flour?
You can, but the texture will be different. Almond flour gives a more tender, melt-in-your-mouth crumble. If using all-purpose flour, use the same weight (60g) and make sure your butter is very cold. The result will be a more traditional, shortbread-like crispness.

My crumble filling is too tart. What can I do?
No problem! Sweetness is so personal. Simply drizzle a little extra maple syrup or honey over each serving when you dish it up. You can also sprinkle the top with a tiny bit of coconut sugar or demerara sugar before baking for an extra caramelized sweetness.

Are the chia seeds noticeable in the final texture?
They add a very slight texture, similar to poppy seeds, but they’re not intrusive at all. Their main job is to thicken the juices, so the overall sensation is of a smooth, jammy berry filling. If you’re sensitive to texture, you can grind the chia seeds into a coarse powder in a spice grinder before adding them—they’ll still thicken perfectly but will be virtually undetectable.