This plum cake is something my mom makes towards the end of summer or early in the fall, when plums are in full bloom. Before she made it, my Grandma Marce made it for us on her summer visits. This recipe is sweeter and more cake like than I remember their's ever being. If that's what you're into, it's perfect.
Consider this version more of a dessert item, like a cakey-cobbler, than a grab-n-go breakfast item. I had some leftover blueberries that I threw into the mix as well, but plums are all you need. Oh yes, and kuchen is the German word for cake. Much better than kaka, which is what they call it in Sweden.
2 1/4 teaspoons or 1 (1/4-ounce) package active dry yeast
1/4 cup warm water (105–110°F)
2 cups plus 2 tablespoons all-purpose flour, divided
1 cup sugar, divided
1/2 teaspoon salt
1/2 cup plain yogurt at room temperature
1 large egg, warmed in shell in warm water five minutes
1 1/2 teaspoons grated lemon zest
1 teaspoon pure vanilla extract
1 1/4 sticks unsalted butter, cut into tablespoons and softened, divided
3/4 pound firm-ripe plums (about 4 small), halved and pitted
Stir together yeast and warm water in mixer bowl and let stand until foamy, about five minutes. (If mixture doesn’t foam, start over with new yeast.)
Add two cups flour, 2/3 cup sugar, salt, yogurt, egg, zest, and vanilla to yeast mixture and mix at medium-low speed 1 minute. Beat in one stick of the butter, one tablespoon at a time, until incorporated. Beat at medium speed until dough is smooth and shiny, about five minutes. (Dough will be very sticky.) Scrape down side of bowl and sprinkle dough with remaining two tablespoons flour. Cover bowl loosely with a kitchen towel or plastic wrap and let dough rise in a draft-free place at warm room temperature until doubled, 1 1/2 to 2 hours.
Spread remaining two tablespoons butter in bottom of an 8- or 9-inch square baking pan and sprinkle with remaining 1/3 cup sugar. Cut each plum half into five or six slices and arrange in one layer in pan.
Stir dough until flour is incorporated, then spread evenly over plums. Loosely cover with buttered plastic wrap, then kitchen towel. Let rise in a draft-free place at warm room temperature until almost doubled, about 1 1/2 hours.
Preheat oven to 375°F with rack in middle. Bake until kuchen is golden-brown and a wooden pick inserted into center comes out clean, 30 to 35 minutes. Cool in pan five minutes, then invert and unmold onto a rack to cool completely.
Serve with additional yogurt, lightly sweetened, or sweetened crème fraîche.
