Winter Squash and Onion Flatbread

Ingredients

• 1 Tbsp. active dry yeast
• 4 cups all-purpose flour, plus more for surface
• 1 Tbsp. kosher salt, plus more
• 3/4 cup plus 1 Tbsp. extra-virgin olive oil, divided, plus more for greasing and drizzling
• 2 delicata squash
• 1 large onion, peeled, cut into thin rounds
• 3-4 sprigs thyme, leaves stripped
• Freshly ground black pepper
• 1/2 cup crumbled mild blue cheese
• 2 cups arugula
• 2 tsp. finely grated lemon zest
• 1 Tbsp. fresh lemon juice

Directions

1. Pour 1½ cups water, warmed to about 110 degrees, into a stand-mixer bowl with the dough hook in place, and add the yeast. Set it aside until the surface turns bubbly, about 10 minutes. Tip in 4 cups flour and 1 Tbsp. salt, then run the mixer on low just until the dough looks rough and shaggy. Stream in ½ cup oil and keep mixing on low until it disappears into the dough. Turn the mixer to medium and knead until the dough comes together evenly, about 6 minutes. Move the dough into a large bowl that has been lightly oiled, and drape a kitchen towel or plastic wrap loosely over the top. Refrigerate until the dough has doubled, about 18 hours.
2. Take the dough out of the refrigerator and allow it to lose its chill, about 1 hour.
3. Spread 3 Tbsp. oil over a large rimmed baking sheet. Dust your work surface with flour, turn the dough onto it, and shape it with a rolling pin into a 16x11" rectangle. Wrap the dough loosely around the rolling pin, lift it onto the oiled sheet, and use your fingertips to ease it out to the sides of the pan. Lay a kitchen towel over it and give it 30 minutes to rest.
4. Heat the oven to 400 degrees. Cut the squash in half lengthwise, scoop away the seeds, then cut it crosswise into ¼"-thick half-moons. Put the squash in a large bowl. Add 2 Tbsp. oil, the onion, and the thyme leaves; add salt and pepper.
5. Arrange the squash mixture across the dough. Finish with a drizzle of oil. Bake for about 45 minutes, until the crust is browned and cooked through, and the vegetables are tender and lightly golden. Set the pan on a wire rack, then scatter the blue cheese across the warm flatbread.
6. When you are ready to serve, put the arugula in a small bowl with the lemon juice and lemon zest, then toss. Slick it with a drizzle of oil, add salt and pepper, and pile the salad over the flatbread.