Winter Squash Galette with Caramelized Onions and Gruyère
Roasted, stuffed or pureed into soup, we’ll eat winter squash any way you make it. So it makes sense that if you take a winter squash, roast it until tender and wrap it in a golden, flaky crust with some melted cheese, we’re ready to marry our dinner. That was the inspiration behind this winter squash galette with caramelized onions and Gruyère.
We made this dish with kabocha squash—aka Japanese pumpkin—but any varietal would work. The pre-roast might seem like a nuisance, but it will ensure the squash is fully cooked by the time you slice into your savory pie. And FYI, the pie crust can be made a full day in advance.
With this recipe in our back pocket, we're ready for whatever winter brings.
2 cups all-purpose flour, plus more for dusting
1 teaspoon kosher salt
1½ sticks cold unsalted butter, cubed
1 tablespoon apple cider vinegar
½ cup ice water
1½ pounds winter squash (such as butternut or kabocha)—peeled, seeded and sliced into ¼-inch wedges
Extra-virgin olive oil, as needed
Kosher salt and freshly ground black pepper
1 medium yellow onion, thinly sliced
4 ounces Gruyère cheese, grated
1 garlic clove, thinly sliced
1 large egg, lighten beaten
2 teaspoons fresh thyme leaves
Flaky salt, to garnish
1. Make the Crust: In the bowl of a food processer, pulse the flour and salt to combine. Add butter, and pulse until it looks like a coarse meal with a few pea-sized lumps of butter remaining, about 10 seconds.
2. Transfer to a large mixing bowl, and sprinkle the vinegar over top. Add ¼ cup of ice water, and use a fork to mix, adding more water as needed until a shaggy dough forms. Turn the mixture out onto a work surface and knead lightly, just until the dough holds in a ball (but don’t overwork it). Flatten into a disk, wrap tightly in plastic wrap and chill for at least 2 hours or up to 1 day.
3. Make the Filling: Preheat the oven to 375°F. Spread the squash into a single layer on an unlined baking sheet. Drizzle with olive oil and season generously with salt and pepper. Transfer to the oven and roast until tender and just starting to caramelize, 20 to 25 minutes. Remove from the oven and cool slightly. (The squash can be made up to 24 hours in advance, stored in the refrigerator.)
4. While the squash is roasting, caramelize the onions. In a medium skillet, heat 2 to 3 tablespoons oil over medium heat. Add the onions and season with a pinch of salt. Reduce the heat to low and cook, stirring occasionally, until the onions are very caramelized and tender, 25 to 30 minutes. Remove from the heat and set aside. (The onions can be made up to 24 hours in advance, stored in the refrigerator.)
5. Assemble the Tart: Preheat the oven to 400°F. On a lightly floured work surface, roll out the dough to a circle about 1/8-inch-thick and 14 inches in diameter. (It doesn’t have to be perfect.) Transfer to a parchment-lined baking sheet.
6. Sprinkle the cheese evenly onto the crust, leaving about a 1-inch border around the edges. Top with the caramelized onions, then arrange the squash evenly on top, tucking the garlic between and underneath the squash slices. Sprinkle with thyme. Fold up the edges of the crust to make a circular galette. Using a pastry brush, brush the crust with the beaten egg. Transfer to the oven and bake until the crust is deeply golden, 45 to 55 minutes. Cool slightly before cutting into wedges.