This recipe is adapted from Gourmet's Plum Kuchen Recipe. Because this is a rich dough with lots of dairy, it doesn't rise as readily as other doughs. Don't be alarmed if your dough doesn't quite double at either rising stage. During the final rise you want to make sure that the dough rises to about half the depth of your pan before adding the toppings and baking.
Having tested the cake several times, I recommend piping the fruit filling on top either using a pastry bag fitted with a large round tip or a makeshift pastry bag made from a Ziploc bag with a hole cut into it. Piping the filling then spreading it allows you to get more uniform distribution without overly disturbing the cake in the process.
- For the Cake:
- 1 (1/4 ounce) package active dry yeast
- 1/4 cup warm water (105-110°F)
- 1/3 cup, plus one teaspoon sugar (about 2 1/2 ounces)
- 2 cups (about 10 ounces) all-purpose flour
- 1/3 cup (about 2 1/2 ounces) about light brown sugar
- 1 teaspoon cinnamon
- 1/4 teaspoon salt
- 1/2 cup (about 4 ounces) sour cream
- 1 large egg
- 1 1/2 teaspoons grated lemon zest
- 2 teaspoons pure vanilla extract
- 8 tablespoons (1 stick) unsalted butter, cut into tablespoons and softened
- For the Fruit Topping:
- 3 1/2 ounces strawberries
- 3 1/2 ounces rhubarb, cut into one-inch pieces
- 1 tablespoon sugar
- 1 ounce orange juice
- 1 teaspoon vanilla
- 2 tablespoons corn starch
- For the Crumb Topping:
- 6 tablespoons butter, cut into tablespoons
- 1/4 cup brown sugar
- 2 tablespoons sugar
- 1 cup flour
- 1/2 teaspoon ginger
- 1/2 teaspoon cinnamon
For the Cake: In the bowl of a stand mixer add yeast, warm water, and one teaspoon sugar. Cover and set aside for 5 minutes or until foamy.
To the yeast mixture add 2 cups flour, sugars, cinnamon, salt, sour cream, egg, lemon zest, and vanilla. Mix on medium speed until just combined, about 45 seconds, then beat in butter, one tablespoon at a time, until thoroughly combined. Continue beating at medium speed until dough is smooth and shiny, about 5 minutes. The dough should be very sticky and stick to the sides of the bowl. Transfer dough to a large greased bowl, cover and let rise in a warm spot until almost doubled, 2 to 3 hours.
Grease an 8-inch baking dish. Spread the dough into the pan and cover with plastic wrap and let rise in a warm and draft-free spot until almost doubled, 1 1/2 hours to 2 hours.
For the Fruit Topping: While your dough is doing its second rise, add strawberries, rhubarb, sugar, orange juice, vanilla and corn starch to the bowl of a food processor. Pulse to puree the fruit. Transfer fruit mixture to a small saucepan and heat over medium, stirring frequently until the mixture thickens. Transfer thickened mixture to a medium bowl and refrigerate until cooled, about 1 hour.
For the Crumbs: Rinse and dry the bowl and blade for your food processor and add butter, sugars, flour, ginger and cinnamon. Pulse until small crumbs form. Transfer to a medium bowl and set aside.
Once dough is ready, set the rack to the middle position and preheat oven to 375°F. Transfer covered dough to refrigerator for 20 minutes to firm it up slightly before adding toppings.
Transfer cooled filling to a piping bag fitted with a large round tip and pipe wide stripes of filling across the top of the cake dough. Use a spreading knife to smooth over filling to cover the entire surface. Toss crumbs, working them with your hands to form them into larger clumps and then sprinkle them over the entire surface of the cake. Bake until crumbs are golden brown and a cake tester inserted in the center of the cake comes out clean, 35 to 45 minutes. Remove, cool and serve. Cover leftovers and store up to a day.
electric stand mixer, 8- by 8-inch glass baking dish, food processor, pastry bag, large round piping tip