Many plum desserts are either too sweet or too soggy. This plum crumble bar is the opposite: it’s buttery, delicately spiced with cinnamon, and holds together with a tender, slightly crumbly whole-grain shortcrust that showcases the bright, jammy plum filling.
Ready in about an hour (plus a short chill), these bars make an ideal weekend baking project. Serve warm with yogurt or a scoop of vanilla ice cream for maximum coziness.
Why these plum crumble bars work
The balance between a buttery crumb base and a slightly thickened plum filling is what makes this recipe stand out.
Using a mix of whole-grain and fine flours gives structure without becoming tough, while ground almonds add richness and a subtle nutty note.
A quick stovetop simmer thickens the plums into a spoonable, not-runny, filling so you don’t end up with a soggy bottom.
The topping is simply the remaining dough broken into coarse crumbs — rustic, forgiving, and visually irresistible.
Ingredients (20 × 20 cm pan)
For the crust and crumble:
- 140 g whole-wheat flour
- 60 g all-purpose flour
- 50 g ground almonds
- 125 g unsalted butter, cold and cubed
- 1 large egg
- 35–45 g granulated sugar or your preferred sweetener, ground if granulated sugar substitute is used
- 1 tsp vanilla powder or extract
- 1 tsp ground cinnamon
- pinch of salt
For the plum filling:
- 500 g ripe plums, pitted and quartered
- 1 heaped tbsp cornstarch mixed with 2 tbsp water (to thicken)
- 1–2 tbsp sugar (optional, depending on plum tartness)
- 1–2 tsp ground cinnamon (don’t be shy)
- 1 tsp lemon juice to brighten the fruit
Make the plum filling (make-ahead friendly)
Cut the plums into quarters and place them in a medium saucepan.
Sprinkle over the cinnamon and a tablespoon of sugar only if the fruit tastes very tart.
Stir over medium heat until the plums soften and release their juices, about 6–8 minutes.
When the fruit starts to break down, stir in the cornstarch slurry and squeeze in the lemon juice.
Cook for another 1–2 minutes until the mixture thickens to a thick-porridge consistency.
Remove from heat and cool to lukewarm; chilling briefly speeds assembly and prevents melting the butter in the dough.
Prepare the crust and crumble
Combine both flours, ground almonds, salt, and the sugar in a bowl.
Work the cold butter in with your fingertips or a pastry cutter until the mix resembles coarse crumbs.
Stir in the cinnamon and vanilla, then add the egg and bring the dough together just until it holds.
Avoid overworking; the dough should be slightly shaggy rather than smooth.
Reserve about one-third of the dough for the topping and press the remaining two-thirds firmly into the bottom of a lined 20 × 20 cm baking pan.
Chill the pan for 20–30 minutes to firm the butter and prevent shrinkage during baking.
Assemble and bake
Preheat the oven to 170°C (fan).
Spread the cooled plum filling evenly over the chilled crust, leaving a small edge if you like a defined border.
Crumble the reserved dough over the plums; press a few larger pieces down to create contrast in texture.
Bake for 30–35 minutes until the top is golden and the filling bubbles slightly at the edges.
Cool fully in the pan to let the filling set, then cut into squares.
Serve warm or at room temperature; they keep well in an airtight container for 3 days.
Pro tips from a pro-friendly baker
If your plums are very juicy, add an extra half tablespoon of cornstarch to avoid a runny filling.
For a deeper flavor, roast the plum quarters at 200°C for 10 minutes before simmering; roasting concentrates their sweetness.
Don’t skip chilling the crust after pressing it into the pan; this step prevents greasy, spread-out crumbs.
If you prefer a softer top, press more of the reserved dough into a thin sheet and lay it over the plums instead of crumbling.
Want a nut-free version? Replace the ground almonds with an equal weight of oat flour.
For a slightly more indulgent finish, brush the warm bars with a thin apricot jam glaze.
Variations worth trying
Make these gluten-free by swapping the wheat flours for a 1:1 gluten-free baking blend and adding 1 tsp xanthan gum if the blend lacks it.
Turn them into a mini tart by pressing the dough into muffin tins and reducing bake time by 5–8 minutes.
If you love layered fruit desserts, these bars pair beautifully with a simple custard or whipped cream.
For a citrus twist, fold some orange zest into the filling to brighten the plum flavor.
Storage and make-ahead
These bars store well at room temperature in a sealed container for up to 48 hours.
For longer storage, refrigerate for up to 5 days or freeze cut squares for up to 3 months.
Reheat gently in a low oven (160°C) for 6–8 minutes to revive the buttery crumb and warm the filling.
Thaw frozen bars at room temperature before reheating for the best texture.
Where this recipe fits in your baking rotation
If you enjoy fruit-forward, autumnal bakes, you might also like this Apple Pie with Yogurt or the buttery Homemade Puff Pastry Apple Tart which uses a similar balance of fruit and crust.
For more crumble-style sweets, check out the Coconut Crumble Pie with Blueberries which follows a comparable approach to fruit and topping.
Looking for inspo on nutty, tender bases? Try the Almond-Glazed Tea Cake.
If you want to experiment with other stone fruits, the Mixed Fruit Plum Cake showcases an alternative way to use plums in a mash-up cake format.
FAQ
Can I use frozen plums?
Yes—thaw them fully and drain excess liquid before cooking to avoid an overly wet filling.
Can I use a different sweetener?
Absolutely. Use honey, maple syrup, or a granulated sugar substitute, adjusting amounts to taste and viscosity.
What if my dough is crumbly and won’t bind?
Add one teaspoon of cold water at a time and gently bring it together; avoid overworking.
How do I stop the bottom from becoming soggy?
Ensure the filling is thick before adding to the crust and chill the pressed base before filling.
Can I make these in a larger pan?
Yes—double everything for a 23–25 cm square or rectangular pan and monitor baking time (add 5–10 minutes).
This recipe rewards attention to balance: a flavorful, spiced plum filling paired with a buttery whole-grain crumble that’s both humble and show-stopping.
Bake a tray this weekend and you’ll see why these bars quickly become a seasonal favorite.
Whole-Grain Cinnamon Plum Crumble Bars
Ingredients
Crust & Crumble
- 140 g whole-wheat flour
- 60 g all-purpose flour
- 50 g ground almonds
- 125 g unsalted butter cold, cubed
- 1 egg large
- 35-45 g granulated sugar or a ground sugar substitute
- 1 tsp vanilla powder or extract
- 1 tsp ground cinnamon
- 1 pinch salt
Plum Filling
- 500 g plums ripe, pitted and quartered
- 1 tbsp cornstarch mixed with 2 tbsp water
- 1-2 tbsp sugar optional
- 1-2 tsp ground cinnamon
- 1 tsp lemon juice
Instructions
Make the Plum Filling
- Place the quartered plums in a saucepan and sprinkle with cinnamon and optional sugar. Cook over medium heat for 6–8 minutes until softened and juicy.
- Stir in the cornstarch slurry and lemon juice. Cook 1–2 minutes until thickened. Cool to lukewarm.
Prepare the Crust & Crumble
- Combine flours, ground almonds, salt, and sugar. Rub in the cold butter until crumbly.
- Mix in cinnamon, vanilla, and egg until the dough comes together.
- Reserve one-third of the dough. Press the rest into a lined 20×20 cm pan and chill for 20–30 minutes.
Assemble & Bake
- Preheat oven to 170°C (fan). Spread the cooled plum filling over the chilled crust.
- Crumble the reserved dough over the filling.
- Bake 30–35 minutes until golden and bubbling. Cool fully before slicing.
Notes
- If your plums are very juicy, add an extra 1/2 tablespoon cornstarch.
- Chilling the crust helps prevent spreading and ensures a crisp base.
- For a nut-free version, substitute ground almonds with oat flour.
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