Grilled Vegetable Pizza – Boomers Forever Young

Ingredients

• 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 zucchinis, 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