Recipe: Summer Squash Gratin

Name: Recipe: Summer Squash Gratin
Ingredients: 4 tablespoons olive oil, divided; 3/4 cup panko breadcrumbs; 1/2 cup grated Parmesan cheese; 2 medium shallots, thinly sliced; 2 cloves garlic, minced; 2 pounds summer squash, cut crosswise into 1/4-inch pieces; 1 tablespoon fresh thyme leaves; 1/2 teaspoon kosher salt