- 2 tablespoons red-wine vinegar
- 1 teaspoon Dijon mustard
- 1 1/2 teaspoons finely chopped fresh oregano
- Kosher salt and freshly ground pepper
- 1/4 cup extra-virgin olive oil, plus more for brushing
- 12 ounces shiitake- or portobello-mushroom caps, or a combination
- 2 medium zucchini, sliced lengthwise into 1/2-inch-thick planks
- 1 bunch lacinato kale, thick stems and center ribs removed
- 1 medium red onion, peeled and cut into 1/2-inch-thick rounds
- 4 store-bought flatbreads, such as Stonefire naan
- 12 ounces low-moisture mozzarella, such as Polly-O, shredded
- 3 ounces blue cheese, crumbled
- Step 1Prepare grill for direct- and indirect-heat cooking. In a bowl, whisk together vinegar, mustard, and oregano; season with salt and pepper. Slowly whisk in oil; set aside.
- Step 2Brush mushrooms, zucchini, kale, and onion with more oil; season with salt. Grill mushrooms over direct heat 6 to 10 minutes, depending on size. Flip mushrooms; add zucchini and onion to grill and cook 5 minutes more. Flip zucchini and onion; add kale to grill.
- Step 3Continue cooking, flipping kale once, until everything is charred in places and cooked through, 3 to 4 minutes more. Transfer to a platter or board. Top flatbreads evenly with about two-thirds of mozzarella. Divide mushrooms and vegetables evenly among flatbreads. Sprinkle with remaining mozzarella and blue cheese.
- Step 4Place pizzas over indirect heat and grill, covered, maintaining a temperature of about 400°F, just until bread is charred in places and mozzarella melts, 7 to 9 minutes (if bread isn’t crisping along bottom and edges, transfer pizzas to direct heat in last minute of cooking). Drizzle with vinaigrette and serve warm.