Harvest Lasagna

Name: Harvest Lasagna
Cuisine: Italian, Mediterranean, European
Ingredients: 3 teaspoons olive oil, divided; 1 bunch escarole or spinach, chopped; 1 tablespoon minced garlic; 1 (15-ounce) container part-skim ricotta cheese; 2 small yellow squash, diced; 1/2 teaspoon salt, divided; 2 cups chopped onions; 1 bunch Swiss chard, chopped; 2 cups prepared marinara sauce; 12 pre-cooked lasagna noodles; 1 cup shredded Fontina cheese