If you still have late-summer fruit ripening on your counter, this easy single-layer Plum Cake is perfect. The cake features a tender vanilla base studded with melted plum pieces and a crisp streusel topping made from brown sugar, cornmeal, and warm ginger. It’s a simple, satisfying treat you’ll want to save.
When plums bake, they collapse into little pools of jammy, sweet-tart flavor. Depending on the variety you use, those jammy pockets can be deep magenta, bright red, or sunny yellow.
I often bake this with Santa Rosa plums because of their intense ruby flesh, but any ripe stone fruit will work — just know the interior color will vary with the variety. I leave the skins on for texture and a touch of tartness.
This is a soft, cottony vanilla cake dotted with melted plum and finished with a crunchy streusel. It’s baked in an 8-inch pan for a perfect single-layer snack or brunch cake.
Technically, this is a “buckle” — a fruit-filled cake topped with streusel. As it bakes, the fruit and crumbs sink and crinkle into the batter, giving the cake its rustic texture and name.
Ingredients
- Brown sugar – 6 tablespoons for the streusel (light or dark).
- All-purpose flour – 1/4 cup for the streusel and 1 1/2 cups for the cake.
- Cornmeal – 2 tablespoons in the streusel for a little crunch.
- Ground ginger – 1/2 teaspoon to add warmth to the topping.
- Salt – a pinch for the streusel and 1/4 teaspoon for the cake.
- Unsalted butter – 1 stick (8 tablespoons / 113 g). Use half cold and diced for the streusel and the rest melted for the batter.
- Plums – 5 small plums (about 10–11 ounces). Use ripe fruit and leave the skins on for flavor and color.
- Granulated sugar – 2/3 cup for the cake batter.
- Egg whites – 2 large (reserve yolks for another use).
- Vanilla – 1/2 teaspoon real vanilla extract.
- Baking powder – 1 1/2 teaspoons.
- Whole milk – 6 tablespoons to keep the cake tender.
How to Make Plum Cake with Streusel Topping
Start with the streusel: whisk brown sugar, 1/4 cup flour, cornmeal, ground ginger, and a pinch of salt. Add the cold diced butter and work it in with your fingertips or a pastry blender until the mixture is crumbly. Set aside.
Wash and dice the plums, leaving the skins on. Small chunks work best; set them aside.
Make the batter: in a medium bowl whisk together the melted butter, granulated sugar, egg whites, and vanilla. Sprinkle the flour, baking powder, and salt over the wet ingredients and gently fold to combine. Add the diced plums and stir again. Finally, add the milk and mix just until no streaks of flour remain — avoid overmixing.
Pour the batter into a lightly buttered 8-inch square pan. Scatter the streusel evenly over the top.
Bake at 350°F (175°C) for 35–38 minutes, until the streusel is golden and a tester inserted comes out mostly clean (a few moist crumbs are fine). Cool slightly, cut into squares, and serve.
Recipe Variations
- Fruit – Swap in any ripe stone fruit: peaches, nectarines, cherries, or other plums work beautifully with the streusel.
- Spices – If ginger isn’t your preference, replace it with the same amount of ground cinnamon or try a pinch of cardamom for a different aromatic profile.
- Dairy – If you don’t have whole milk, half-and-half is a fine substitute. Plant-based milks can be used in a pinch but may alter texture since they contain less protein.
Make Ahead
You can bake this cake up to a day ahead and keep it tightly wrapped at room temperature. Leftovers refrigerate for up to three days, though the streusel will soften with storage.
Plum Cake
Ingredients
Streusel:
- 6 tablespoons brown sugar
- 1/4 cup flour
- 2 tablespoons cornmeal
- 1/2 teaspoon ground ginger
- Pinch of salt
- 4 tablespoons cold butter diced
Plum Cake:
- 5 small plums 10-11 ounces
- 4 tablespoons butter melted
- 2/3 cup granulated sugar
- 2 large egg whites
- 1/2 teaspoon vanilla
- 1 1/2 cups flour
- 1 1/2 teaspoons baking powder
- 1/4 teaspoon salt
- 6 tablespoons whole milk
Instructions
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Preheat oven to 350°F (175°C). Lightly butter an 8-inch square baking pan.
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Make the streusel: whisk brown sugar, flour, cornmeal, ginger, and a pinch of salt. Rub in the cold diced butter with your fingertips until crumbly. Set aside.
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Slice, pit, and dice the plums into small pieces, leaving the skins on. Set aside.
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In a medium bowl, whisk melted butter, granulated sugar, egg whites, and vanilla.
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Sprinkle the flour, baking powder, and salt over the mixture and stir gently to combine.
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Add the diced plums and the milk. Stir until just combined; do not overmix.
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Pour the batter into the prepared pan and sprinkle the streusel over the top.
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Bake 35–38 minutes, until the streusel is golden and a tester comes out mostly clean. Cool slightly, cut into squares, and enjoy.