German Rhubarb Streusel Cake
Tender vanilla cake provides a soft and buttery foundation.Fresh rhubarb adds a naturally tart and refreshing fruit layer.Sugar balances the sharpness of the rhubarb.Golden streusel creates a sweet, crumbly topping.The cake is baked until the rhubarb is tender and the crumbs are golden.Perfect for spring gatherings, afternoon coffee, and family dessert.
Ingredients
For the Cake
- 2 cups (250 g) all-purpose flour
- 2 teaspoons baking powder
- ¼ teaspoon salt
- ¾ cup (170 g) unsalted butter, softened
- ¾ cup (150 g) granulated sugar
- 3 large eggs
- 1 teaspoon vanilla extract
- ½ cup (120 ml) whole milk
For the Rhubarb Layer
- 4 cups (500–600 g) fresh rhubarb, cut into ½-inch pieces
- ½ cup (100 g) granulated sugar
- 2 tablespoons cornstarch
- 1 teaspoon vanilla extract
- 1 tablespoon fresh lemon juice
For the Streusel
- 1 cup (125 g) all-purpose flour
- ½ cup (100 g) granulated sugar
- ½ cup (115 g) cold unsalted butter, cubed
- ½ teaspoon ground cinnamon
- Pinch of salt
For Finishing
- Powdered sugar, optional
- Whipped cream, optional
- Vanilla ice cream, optional
Instructions
Prepare the Oven and Pan
- Preheat the oven to 350°F (175°C).Grease and line a 9×13-inch (23×33 cm) baking pan with parchment paper.Leave some parchment hanging over the sides to make removing the finished cake easier.
Prepare the Rhubarb
- Wash the rhubarb thoroughly and trim away the leaves and ends.Cut the stalks into approximately ½-inch pieces.Place the rhubarb in a bowl and toss it with sugar, cornstarch, vanilla, and lemon juice.Set aside for about 10 minutes.The cornstarch will help absorb some of the fruit juices during baking.
Add the Milk and Flour
- Add approximately one-third of the flour mixture to the butter mixture.Mix gently.Add half of the milk and continue alternating the flour and milk, finishing with the flour.Mix only until combined.Do not overmix the batter.
Spread the Cake Batter
- Transfer the batter to the prepared baking pan.Use a spatula to spread it evenly across the bottom.The batter will be relatively thick.
Add the Rhubarb
- Spread the prepared rhubarb evenly over the cake batter.Try to distribute the fruit in a single relatively even layer.Some rhubarb pieces may sink slightly during baking, which is perfectly fine.
Prepare the Streusel
- Place the flour, sugar, cinnamon, and salt in a bowl.Add the cold cubed butter.Use your fingertips or a pastry cutter to rub the butter into the flour mixture until coarse crumbs form.The mixture should contain a variety of small and medium-sized crumbs.Do not knead it into a smooth dough.
Add the Streusel
- Sprinkle the streusel evenly over the rhubarb layer.Make sure the fruit is generously covered without pressing the crumbs down.
Cool
- Remove the cake from the oven and place it on a wire rack.Allow it to cool in the pan for at least 30 minutes.For cleaner slices, allow the cake to cool completely.
Finish and Serve
- Dust the cooled cake lightly with powdered sugar if desired.Cut into squares and serve with whipped cream or vanilla ice cream.The cake is delicious at room temperature and especially comforting when served slightly warm.
Notes
- Use fresh rhubarb: Choose firm, brightly colored stalks without soft or damaged areas.
- Never use rhubarb leaves: Rhubarb leaves are not considered safe to eat and should always be discarded.
- Adjust the sugar: Very tart rhubarb may require slightly more sugar depending on personal preference.
- Do not skip the cornstarch: It helps manage the liquid released by the rhubarb.
- Keep the streusel cold: Cold butter helps produce distinct, crumbly pieces.
- Avoid overmixing: Overworked cake batter can become dense.
- Cool before slicing: The fruit layer firms as the cake cools.
- Check the cake portion: Insert a toothpick into the cake rather than directly into a juicy piece of rhubarb.