Raspberry-Plum Crumb Tart
You'll need a springform pan for this recipe. It is also important to use firm plums; soft ones will prevent the custard filling from setting properly.
- 3/4 cup unsalted butter (1 1/2 sticks), chilled, cut into small pieces, plus more for pan
- 1/3 cup hazelnuts
- 1 1/2 cups plus 1 tablespoon all-purpose flour
- 3/4 cup plus 2 tablespoons granulated sugar
- 1/3 cup packed light-brown sugar
- 3/4 teaspoon ground cinnamon
- 3/4 teaspoon salt
- 3 medium-size, ripe but firm plums (about 12 ounces)
- 1 half-pint raspberries
- 1 large egg, lightly beaten
- 1 large egg yolk
- 1/3 cup heavy cream
- 1/4 cup milk
- Grated nutmeg, optional
Heat oven to 350 degrees. Butter a 9-inch springform pan; set aside. Spread hazelnuts on a baking sheet. Bake until fragrant, about 10 minutes. Rub warm nuts in a clean kitchen towel to remove skins. Let cool. Place nuts in the bowl of a food processor, and pulse until medium fine, about 30 pulses.
Transfer nuts to the bowl of an electric mixer fitted with the paddle attachment. Add 1 1/2 cups flour, 1/2 cup granulated sugar, light-brown sugar, 1/2 teaspoon cinnamon, and 1/2 teaspoon salt; mix until just combined. Add butter, and mix on low speed until crumb begins to stick together, 2 to 3 minutes. Press 3 cups of crumb into the bottom of the prepared pan and about 1 1/2 inches up the sides of the pan to form crust. Set remaining crumb mixture aside.
Transfer crust to the oven; bake until it appears to be set, 18 to 20 minutes. Set aside.
Slice plums in half, and remove pits. Slice into eighths. Scatter 3/4 cup raspberries and sliced plums onto cooled crust; set aside.
In a medium bowl, whisk together 1 tablespoon flour and 1/4 cup plus 2 tablespoons granulated sugar. Whisk in egg, egg yolk, heavy cream, milk, 1/4 teaspoon cinnamon, 1/4 teaspoon salt, and nutmeg (optional). Pour custard over fruit; sprinkle with remaining crumb mixture. Transfer tart to the oven; bake until custard has set and is slightly golden, 45 to 50 minutes. Garnish with remaining raspberries. Let rest at least 25 minutes before cutting. Serve warm or at room temperature.