The irresistible buttery, spiced oat topping and perfect balance of sweet to tart in the fruity filling make this a recipe we reach for every summer. Carolyn Beth Weil, author of Williams-Sonoma Pie & Tart (Simon & Schuster, 2003), created it for Sunset years ago. Serve this fresh raspberry-rhubarb crisp with lightly sweetened softly whipped cream or vanilla ice cream.
1 cup regular rolled oats
1/2 cup all-purpose flour
1/2 cup finely chopped walnuts (2 1/2 oz.)
1/2 cup packed light brown sugar
1/2 teaspoon ground cinnamon
1/2 teaspoon ground ginger
1/8 teaspoon salt
1/2 cup (1/4 lb.) cold butter, cut into chunks
3/4 cup granulated sugar
2 tablespoons cornstarch
1 qt. raspberries, rinsed and drained (18 oz.)
3 cups sliced rhubarb (cut 1⁄2 in. thick; about 12 oz.)
How to Make It
Preheat oven to 350°. Combine oats, flour, walnuts, brown sugar, cinnamon, ginger, and salt in a large bowl. With your fingers, rub butter into oat mixture until blended and coarse lumps form. Cover and chill.
Combine granulated sugar and cornstarch in another large bowl. Add raspberries and rhubarb and toss gently to combine with cornstarch mixture. Pour into a shallow 2- to 3-qt. baking dish and sprinkle evenly with topping.
Bake crisp until topping is golden brown and fruit is bubbling, about 45 minutes. Serve warm or at room temperature, with ice cream.
Make ahead: The topping, up to 1 day, chilled airtight.