Fish Milanese with Summer Squash

Name: Fish Milanese with Summer Squash
Ingredients: 4 sole or flounder fillets (about 1 1/2 pounds); Kosher salt and freshly ground pepper; 1 cup all-purpose flour; 2 large eggs, beaten; 2 cups panko; 1/2 cup mayonnaise; 3 tablespoons buttermilk; Juice of 1/2 lemon, plus wedges for serving; 3 scallions, thinly sliced (greens reserved for topping); 1 large zucchini; 1 large yellow squash; 2 tablespoons white wine vinegar or champagne vinegar; 2 tablespoons vegetable oil, plus more for frying