German Rhubarb Streusel Cake - cooking recipe

Ingredients

2 cups all-purpose flour
1 egg
1/2 cup white sugar
2 teaspoons vanilla sugar
1/2 cup unsalted butter, cubed and softened
3 1/2 cups chopped rhubarb
3 tablespoons white sugar
2 tablespoons unsalted butter, cut into cubes

Preparation

Sift flour into a large bowl and make a well in the middle. Add egg, 1/2 cup sugar, and vanilla sugar to the well. Distribute 1/2 cup cubed butter evenly on top. Mix into a dough using your hands. Cover and refrigerate for 30 minutes.
Preheat the oven to 325 degrees F (165 degrees C). Grease a 9-inch springform pan.
Place 2/3 of the dough in the springform pan and smooth across the bottom. Cover with rhubarb.
Crumble remaining dough between your fingers and sprinkle over the rhubarb. Sprinkle with 3 tablespoons sugar. Scatter 2 tablespoons cubed butter over the streusel.
Bake in the preheated oven until streusel is lightly brown and crisp, 30 to 40 minutes.