Maple-Roasted Butternut Squash, Chard, And Sausage Flatbread

Ingredients

• 1 lb. pizza dough, thawed if frozen
• 1 lb. butternut squash, peeled, halved lengthwise, seeded, and sliced crosswise 1/4 inch thick
• 3 tbs. pure maple syrup
• 2 tbs. extra-virgin olive oil
• kosher salt and freshly ground black pepper
• semolina or cornmeal, for dusting the pan
• 1/2 small red onion, thinly sliced (3/4 cup)
• 1 tbs. fresh thyme, coarsely chopped
• 6 oz. fresh pork sausage (hot or sweet), removed from casings if necessary, and crumbled
• 6 oz. fresh whole-milk ricotta (3/4 cup)
• 3/4 oz. finely grated pecorino romano (3/4 cup using a rasp grater)
• 1 tsp. apple cider vinegar
• 2 cups very thinly sliced rainbow chard leaves