Grilled Pizza Pockets With Balsamic Mushrooms

Name: Grilled Pizza Pockets With Balsamic Mushrooms
Ingredients: 2 Tbsp. balsamic vinegar; 2 tsp. Dijon mustard; 1/4 tsp. grated garlic (from 1 clove); 3/4 tsp. kosher salt, divided; 1/4 cup plus 3 Tbsp. extra-virgin olive oil, divided, plus more for grill; 1 lb. fresh pizza dough, cut into 4 pieces, at room temperature; 1 lb. small portobello mushroom caps, stemmed; 1 cup whole-milk ricotta cheese; 2 cups loosely packed salad greens (from a 5-oz. pkg.); 1/2 cup sliced sweet pickled cherry peppers (from a 16-oz. jar)