Fruit Crumble with Buckwheat Biscuits

1. Mixed Berry Crumble

Ingredients / Topping

Ingredients / Filling

Method

Quantities refer to the 150 g biscuits portion. For other amounts see the ingredients table.

1. Place 150 g biscuits in a bag and crush with a rolling pin into irregular crumbs (some hazelnut-sized, some like breadcrumbs). Do not reduce to powder.



2. In a bowl, rub 40 g cold butter, cubed into the crumbs with your fingertips until the mix barely holds together when pressed but crumbles easily.



3. Add 30 g rolled oats, 30 g roughly chopped hazelnuts, 15 g brown sugar and 1.5 g fine salt. Mix. Refrigerate for at least 15 minutes.



4. Preheat the oven to 190°C (fan 180°C).
5. In a large bowl, toss 600 g mixed berries (fresh or frozen, do not thaw) with 50 g caster sugar, 15 ml lemon juice, 12 g cornstarch and grated zest of half a lemon.





6. Pour the fruit mixture into a baking dish (approx. 20×25 cm).
7. Scatter the cold topping over the fruit without pressing it down; leave small gaps at the edges.



8. Bake 30-35 minutes until the topping is deep golden and the juices bubble at the edges.
9. Let rest 10-15 minutes out of the oven before serving.





10. Serve warm with Greek yogurt or vanilla ice cream.

2. Variation: Cherry Crumble

Ingredients / Topping

Same as the main recipe.

Ingredients / Filling

Method

Quantities refer to the 150 g biscuits portion. For other amounts see the ingredients table.

1. Place 150 g biscuits in a bag and crush with a rolling pin into irregular crumbs. Do not reduce to powder.
2. In a bowl, rub 40 g cold butter, cubed into the crumbs with your fingertips until the mix barely holds together when pressed but crumbles easily.
3. Add 30 g rolled oats, 30 g roughly chopped hazelnuts, 15 g brown sugar and 1.5 g fine salt. Mix. Refrigerate for at least 15 minutes.
4. Preheat the oven to 190°C (fan 180°C).
5. In a large bowl, toss 600 g pitted cherries with 40 g caster sugar, 15 ml lemon juice, 9 g cornstarch, 15 ml red wine vinegar and 5 ml vanilla extract.
6. Pour the fruit mixture into a baking dish (approx. 20×25 cm).
7. Scatter the cold topping over the fruit without pressing it down; leave small gaps at the edges.
8. Bake 30-35 minutes until the topping is deep golden and the juices bubble at the edges.
9. Let rest 10-15 minutes out of the oven before serving.
10. Serve warm with Greek yogurt or vanilla ice cream.

3. Storage

• In the fridge, tightly covered: 3–5 days. Crunchiness decreases over time; reheat in the oven at 175°C for 10 minutes before serving.
• Unbaked topping: freeze in an airtight bag for up to 3 months. Use straight from frozen, without thawing.
• Baked topping: can be frozen wrapped in plastic film and then foil/plastic, for 2–3 months. Thaw overnight in the fridge, then reheat in the oven at 175°C for 10–15 minutes to restore crunchiness. Microwaving is not recommended (it makes the texture chewy).

4. Notes on brown sugar

5. Mixed berries: with or without apples?

6. Butter alternatives in the topping

The role of butter in crumble

Butter in crumble is not a simple fat; it is composed of ~80% fats, ~16-18% water and ~1-2% milk solids. The technique used to combine butter and flour (or crumbled biscuits, as in this recipe) is rubbing in: cold butter is rubbed into the flour/biscuits, creating fat flakes that coat the starch particles and prevent gluten formation. During baking the fat melts (32-35°C) creating empty pockets, the water evaporates (100°C) lightening the structure, and the milk solids trigger the Maillard reaction (140-165°C) for browning and nutty flavour. Temperature is an important parameter: the butter must be cold (10-14°C) to remain plastic without melting in your hands.

Coconut oil: an ideal substitute

Coconut oil is an effective substitute because it is a vegetable fat that is solid at working temperature. Use the refined version (odourless) to avoid altering the flavour profile. Ratio: 85-90% of the butter weight.

1. Solidify the coconut oil in the fridge for at least 2 hours (it should be as hard as cold butter)
2. Cut into ~1 cm cubes straight from the fridge
3. Proceed with the classic rubbing-in method, working quickly (coconut oil melts faster than butter)
4. Return the topping to the fridge for 15-20 minutes before baking

Liquid vegetable oils (olive, sunflower, corn)

These produce a more compact, biscuit-like crumble. Seed oil (sunflower, corn) is completely neutral and works with any fruit, including mixed berries and cherries. Ratio: 75% of the butter weight. The oil temperature is not relevant; the critical step is freezing afterwards.

1. Mix all dry ingredients (crumbled biscuits, oats, hazelnuts, sugar, salt)
2. Drizzle in the oil while mixing with a fork until irregular clumps form
3. If the mixture is too dry to form crumbs, add 1-2 tablespoons of milk
4. Freeze the topping for 20-30 minutes before baking

Margarine

Modern margarines, free of trans fats and hydrogenated fats, replace butter 1:1 with the same rubbing-in technique. The result is visually similar but with less flavour (the milk solids for Maillard browning are missing).

Non-fat alternatives (not equivalent!)

I include these possible substitutions for completeness, as I have seen them used, but I have never tried them personally. They are vegetable alternatives, to varying degrees healthier, which however alter the type of final product. The result will not be worse; it will be different, moving away from a crumble.

• Tahini: substitute 1:1, mix with a fork into the dry ingredients, freeze 15-20 minutes. The toasted sesame notes pair well with buckwheat. Result is more compact, cookie-like.
• Greek yogurt: replace only 50% of the butter (50% butter + 50% yogurt). Result like a crumbled scone, not a true crumble.
• Fruit purées: max 50% of the fat. The result is not a crumble; it becomes a soft topping.

Comparison table

Principles for substitution

1. Physical state of the fat: if solid at 10-14°C (coconut, margarine), you can do the classic rubbing in. If liquid (oil), use the "fork mix + freeze" technique.
2. Compensate for missing water: coconut oil is pure fat; add 1-2 tablespoons of liquid per 100 g of fat.
3. Compensate for missing Maillard: without milk solids, browning will be less. Add 1-2 tablespoons of milk powder to the topping.
4. Oven temperature: with fats that have a low melting point, increase by 5-10°C (from 190 to 195-200°C).

7. Aromatic Compatibility Ranking

From best to lowest affinity with buckwheat.

8. Technical Notes and Variations

9. Professional Sources Consulted