Turnip and Kale Gratin

Name: Turnip and Kale Gratin
Ingredients: 5 garlic cloves, thinly sliced; 2 cups heavy cream; ½ teaspoon dried thyme; 2 tablespoons unsalted butter, divided; 3 medium onions, thinly sliced; Kosher salt; 3 bunches Tuscan kale, ribs and stems removed, leaves torn; 4 medium turnips (about 1¾ pounds total), trimmed, peeled, cut into ½-inch pieces; 3 large eggs, beaten to blend; 4 ounces Fontina cheese, grated (about 1 cup); 1 ounce Parmesan, finely grated (about 1 cup); 8 ounces day-old white country-style bread, cut into ½-inch pieces; Freshly ground black pepper