You can make this recipe through step two up to one day in advance; cover it with plastic wrap and refrigerate. The crumb topping can also be made one day ahead; store it separately in an airtight container in the refrigerator.
- 3/4 cup (1 1/2 sticks) chilled unsalted butter, cut into 1/2-inch pieces, plus more for dish
- 3 tablespoons extra-virgin olive oil
- 3 small butternut squash (about 4 pounds total), peeled and cut into 3/4-inch chunks
- Coarse salt and freshly ground pepper
- 2 large shallots, thinly sliced
- 1/4 cup coarsely chopped fresh flat-leaf parsley
- 1/2 cup homemade or low-sodium canned chicken stock
- 1 1/2 cups all-purpose flour
- 3/4 teaspoon sugar
- 2 tablespoons fresh thyme
- 1 teaspoon table salt
- 2 large egg yolks
- 3 to 4 tablespoons ice water
Preheat oven to 375 degrees. Generously butter a 10-inch round gratin dish; set aside. Heat 1 tablespoon oil in a large skillet over medium-high heat. Add half the squash, and season with coarse salt and pepper. Cook, stirring occasionally, until well browned, 8 to 10 minutes. Transfer to prepared dish. Repeat with another tablespoon oil and remaining squash, and transfer to prepared dish. Set aside.
Reduce heat to medium; add remaining tablespoon oil and the shallots to skillet. Cook, stirring frequently, until the shallots are lightly browned, 3 to 5 minutes. Transfer the shallots to baking dish along with parsley and stock; stir well to combine. Cover dish tightly with foil, and bake, stirring occasionally, until squash is just tender, about 30 minutes.
Meanwhile, place flour, sugar, thyme, and table salt in a food processor; pulse to combine. Add butter, and process until mixture resembles coarse meal. Whisk together the yolks and 3 tablespoons ice water in a small bowl; add to flour mixture. Pulse until the mixture just comes together. If crumble is too dry, add remaining tablespoon ice water.
Remove the squash from oven, and remove foil. Arrange the crumble on top. Return to oven, and bake until the topping is golden brown and the squash is very tender, about 30 minutes. Serve warm or at room temperature.