Winter Squash and Onion Flatbread

Name: 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; ¾ cup plus 1 Tbsp. extra-virgin olive oil, divided, plus more for greasing and drizzling; 2 delicata squash (about 2 lb. total); 1 large onion, peeled, cut into thin rounds; 3–4 sprigs thyme, leaves stripped; Freshly ground black pepper; ½ cup crumbled mild blue cheese (such as Danish Blue or Cambozola); 2 cups arugula; 2 tsp. finely grated lemon zest; 1 Tbsp. fresh lemon juice