German Plum Poppy Seed Crumble Cake
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Deutsch (German)
If you love traditional German baking, this German Plum & Poppy Seed Crumble Cake is a must-try. Buttery shortcrust, a creamy homemade poppy seed filling (no canned Mohnback here!), juicy Italian prune plums, and a crunchy streusel topping. It’s the perfect late-summer and fall German plum cake and a cozy twist on the more common German poppy seed cake (Mohnkuchen).
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In Germany, we take poppy seeds seriously. They’re not just a sprinkle on a roll — in German baking, they’re often the star of the show. And this German Plum Poppy Seed Crumble Cake with Pudding and Streusel Topping is a perfect example of how generously we use them in baking.
A creamy poppy seed custard filling is layered with late-summer plums and topped with buttery streusel — pure comfort on a plate.
Why You’ll Love This Recipe
- The creamy poppy seed layer looks so impressive and adds a nutty, almost almond-like flavor.
- It’s the perfect seasonal bake to celebrate plum season.
- Pudding + streusel + plums = a cozy German classic with a twist.

Where to buy poppy seeds for baking German cakes
In Germany, they’re available in every supermarket. In the US/Canada, check the baking aisle, specialty European shops, or order online. I had luck with these poppy seeds from Amazon as they come in a. 1 lbs package. They come as whole seeds, so you need to grind them before using, which you can do in a small food processor or a coffee mill.
The original German recipe also uses Vanilla Custard Powder ( this brand) but you can use cornstarch instead and add some vanilla.
Also, freel free to swap plums for apricots or sour cherries. Add a hint of cinnamon to the streusel for extra warmth or use almond extract in the filling for a nutty twist.

Regular plums or even firm black/purple plums will work. Just make sure they’re ripe but not too juicy — you don’t want the cake to become soggy. Slice them in halves or quarters, and if they’re very juicy, dust with a bit of cornstarch before layering.
YES – Ground poppy seeds give a smoother filling plus they thicken the custard in a way whole poppy seeds won’t. You can blitz them in a spice grinder.
Yes, substitute a good 1:1 gluten-free baking flour for the base and streusel.
Tips
- Storage: The cake keeps well in the fridge for up to 3 days. The streusel will soften a bit, but the flavors meld beautifully.
- Freezing: You can freeze leftovers in slices. Just wrap tightly and thaw at room temperature before serving.
- Make Ahead: Bake a day in advance; the flavors of the poppy seeds and plums deepen overnight
If you love baking with poppy seeds, try my German Poppy Seed Marzipan Cookies (Spritzgebäck) and my German Poppy Seed Sheet Cake with Streusel

German Plum Poppy Seed Cake with Streusel
Ingredients
Shortcrust Pastry
- 350 g 2 ¾ cups all-purpose flour
- 80 g ⅓ cup + 1 Tbsp sugar
- 1 pinch salt
- 175 g ¾ cup + 2 Tbsp cold butter, cubed
- 1 egg large
- A few drops almond extract optional
Poppy Seed Pudding Filling
- 750 ml 3 cups whole milk
- 2 packages 37 g each / 3 oz total vanilla or almond pudding powder (see note for cornstarch substitute)
- 165 g ¾ cup + 2 Tbsp sugar
- 200 g 1 ¾ cups ground poppy seeds
- 1 Tbsp dark rum optional
- 💡 Substitution: If you can’t find pudding powder use 6 Tbsp cornstarch + 4 Tbsp sugar + 2 tsp vanilla extract in its place (this equals about 2 standard pudding packets).
Fruit Layer
- about 12 Italian prune plums pitted and quartered
- 1 Tbsp brown sugar mixed with a pinch of cinnamon
Instructions
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Make the shortcrust pastry:
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Mix flour, sugar, and salt in a large bowl. Add butter cubes and rub into the flour mixture until crumbly. Add the egg and quickly knead into a streusel-like dough.
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Use about two-thirds of the dough for the base and sides: Press directly into a greased and parchment-lined 26 cm / 10-inch springform pan (no rolling needed). Form small “sausages” with pieces of dough, press them along the inside edge, and shape into a rim about 3 cm (1 inch) high. Chill the remaining dough in the fridge for later.
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Make the poppy seed pudding filling:
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In a saucepan, whisk together cold milk, pudding powder (or cornstarch substitute), sugar, and poppy seeds. Bring to a boil, stirring constantly, and cook until thickened. Remove from heat, stir in rum if using, and let cool for about 10 minutes.
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Assemble the cake:
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Pour the poppy seed filling into the crust and smooth out. Arrange the quartered plums on top and sprinkle with the brown sugar-cinnamon mix.
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Add the streusel topping:
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Take the reserved dough from the fridge and crumble it evenly over the plums.
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Bake:
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Bake in a preheated oven at 160°C / 320°F (top/bottom heat) for about 60 minutes. The low temperature ensures the crust doesn’t brown too quickly, the filling sets gently, and the streusel turns golden without burning.
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Alternative: Bake at 180°C / 350°F for 45–50 minutes, but cover the streusel with foil toward the end to prevent over-browning.
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Cool & serve:
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Let cool completely before removing from the pan. Serve with whipped cream if desired.