My dad grew up in the Bronx of the 1920s and was very fond of the yeasty crumb cakes found in many German-Jewish bakeries there. He calls the moist, tender cakes "crumb buns" and loves to eat them with a cup of coffee.

1 (1/4-ounces) package active dry yeast (2 1/2 teaspoons)

1 cup warm whole milk (105115°F)

1/2 cup plus 1 tablespoon sugar

1 tablespoon fresh lemon juice

3 3/4 cups plus 2 tablespoons all-purpose flour

1 1/2 teaspoons salt

2 large eggs, at room temperature for 30 minutes

1 1/2 teaspoons vanilla

1 1/2 sticks (3/4 cup) unsalted butter, cut into tablespoon pieces and softened slightly

1 1/2 cups all-purpose flour

3/4 cup sugar

1 1/2 teaspoons cinnamon

1 1/2 sticks (3/4 cup) cold unsalted butter, cut into small pieces

1 teaspoon vanilla

a stand mixer fitted with paddle attachment

PreparationMake dough: Stir together yeast, 1/4 cup warm milk, and 1 tablespoon sugar in bowl of mixer until yeast is dissolved, then let stand until foamy, about 5 minutes. (If mixture doesn't foam, discard and start over with new yeast.) Stir together lemon juice and remaining 3/4 cup milk and let stand until curdled, 1 to 2 minutes. Add 3 3/4 cups flour to yeast mixture along with salt, eggs, vanilla, and remaining 1/2 cup sugar and mix at low speed until just combined. Add curdled milk and beat at medium speed until a dough forms. Add butter, 1 piece at a time, beating, then continue to beat until dough is silky and elastic, 5 to 8 minutes. (Dough will be very sticky.) Sprinkle with remaining 2 tablespoons flour and cover bowl with a clean kitchen towel (not terry cloth). Let dough rise in a draft-free place at warm room temperature until doubled in bulk, 1 1/2 to 2 hours. Make topping: Pulse together topping ingredients in a food processor until many large clumps form. Transfer to a bowl and chill, covered, until ready to use. Form and bake cake: Butter a 13- by 9-inch baking dish or pan. Stir dough several times with a rubber scraper to release air, then spread evenly in baking dish. Sprinkle dough with half of topping, then cover dish with kitchen towel and let dough rise again in a draft-free place at warm room temperature until almost doubled in bulk, 1 to 1 1/2 hours. Put oven rack in middle of oven and preheat oven to 350°F. Sprinkle remaining topping over top of cake and bake until topping is golden, 55 to 60 minutes. Cool cake in pan on a rack until barely warm, then cut into squares. Cooks' NoteCrumb cake is best when freshly made, but leftovers can be rewarmed, wrapped in foil, in a 350°F oven.