- 1 stick (1/2 cup) plus 1 tablespoon unsalted butter, room temperature, plus more for pan
- 2 cups plain whole-milk yogurt
- 1 pound rhubarb, trimmed and cut crosswise into 3-inch pieces
- 1 1/2 cups sugar, plus more for sprinkling
- 1 3/4 teaspoons kosher salt
- 1/2 cup shelled unsalted pistachios (2 1/4 ounces)
- 1 1/2 cups unbleached all-purpose flour
- 2 teaspoons baking powder
- 2 large eggs, room temperature
- 1 1/4 teaspoons pure vanilla extract or orange-blossom water
- 1/4 cup confectioners' sugar
- Preheat oven to 400 degrees. Butter an 8-inch-round, 2-inch-deep cake pan and line bottom with parchment; butter parchment. Place 1 cup yogurt in a fine-mesh sieve set over a bowl; let drain in refrigerator.
- Meanwhile, toss together rhubarb, 1/2 cup granulated sugar, 1 tablespoon butter, and 1/4 teaspoon salt on a rimmed baking sheet. Roast, stirring once, just until tender, about 15 minutes. Reduce oven temperature to 325 degrees.
- In a food processor, finely grind pistachios. Add flour, baking powder, and remaining 1 1/2 teaspoons salt; pulse to combine. Beat together remaining 1 stick butter and 1 cup granulated sugar with a mixer on medium-high speed until light and fluffy. Beat in eggs, one at a time, then vanilla. Reduce speed to low and beat in flour mixture in two batches, alternating with remaining 1 cup yogurt.
- Transfer batter to pan and smooth top. Arrange about half of rhubarb over top; refrigerate remaining rhubarb in syrup until ready to serve. Sprinkle cake with granulated sugar and bake until a tester inserted in center comes out clean, about 1 hour, 15 minutes (if browning too quickly, tent with foil). Transfer pan to a wire rack and let cool 15 minutes. Run a small sharp knife around edges. Invert onto a cutting board, then immediately flip onto rack; let cool completely.
- Stir confectioners' sugar into drained yogurt. Chop remaining rhubarb and swirl into yogurt, along with some syrup. Serve cake with yogurt, drizzled with more syrup.
Tips/TechniquesWhen Martha made this recipe on Martha Bakes episode 1103, she omitted the drained yogurt and confectioners’ sugar and served the cake with lightly sweetened whipped cream instead. She also dusted the parchment with flour after buttering it in step 1, and sprinkled the cake with about 2 tablespoons granulated sugar in step 4.