1. Preheat oven to 350°.
2. Melt butter in a large nonstick skillet over medium-high heat. Add corn and green onions; sauté 5 minutes. Remove from heat.
3. Combine milk and eggs in a large bowl, stirring with a whisk. Add ricotta cheese and next 5 ingredients (through pepper), stirring with a whisk. Stir in 1 cup cheddar cheese and corn mixture; pour into a 2 1/2-quart glass or ceramic baking dish coated with cooking spray. Sprinkle with 1/2 cup cheddar cheese.
4. Bake at 350° for 45 minutes or until set. Garnish with basil, if desired.