Grilled summer squash flavored with za’atar makes for a fresh, seasonal topping for these individual weeknight dinner pizzas. Simply grilled pizza dough is topped with a light layer of melted cheese and the squash, and is then finished with crumbled feta, cilantro and lemony red onions.
Preheat a grill to medium. Combine the red onion, lemon juice and a big pinch of salt in a medium bowl; toss well. Cut the pizza dough into 4 pieces. On a lightly floured surface, press one piece of dough with your fingertips to make a 4- to 5-inch round, then roll out into an 8-inch round. Repeat with the remaining dough.
Combine the zucchini and/or yellow squash, 2 tablespoons olive oil, 3/4 teaspoon salt and the red pepper flakes in a large bowl; toss well to coat. Grill until well marked and tender, 2 to 3 minutes per side. Remove to a plate.
Combine 2 tablespoons za’atar, a pinch of salt and the remaining 3 tablespoons olive oil in a small bowl. Grill the dough rounds until marked on the bottom and starting to bubble up in spots, about 3 minutes. Flip the dough, brush with the za’atar oil and top with the mozzarella and zucchini and/or squash. Cook until the dough is marked on the bottom and the mozzarella melts, about 3 minutes.
Remove each flatbread to a plate, scatter the feta and red onion on top and sprinkle with the remaining 1 teaspoon za’atar, a pinch of salt and the cilantro.