Frittatas are a perfect "Meatless Monday" meal. They are quick and easy to make. The ingredients are simple staples to keep on hand. No rush to the grocery store is required. A bonus for Monday meal planning!
In a large sauté pan, set over medium heat, add the butter and olive oil. Just as it begins to sizzle, add the onions, tomatoes, and spinach. Cook for 8 to 10 minutes. Add the garlic in the last minute of cooking.
Meanwhile, whisk the eggs in a small mixing bowl, add the water, basil, Parmesan cheese, and vegetable mixture.
Heat a well-seasoned, ovenproof 9" skillet over medium heat until it's quite hot. Add 1 tablespoon olive oil and swirl to coat the pan.
Add the egg mixture. Cook, occasionally lifting the sides so the uncooked portion can flow underneath. Cooking time will be about 5 to 8 minutes or until the edges are set and the bottom is golden.
Place the skillet about 6 inches from the boiler element. Broil for until the top is set and golden, about 4 to 5 minutes. Watch closely!
Slice into wedges. Place on serving plates. Garnish with fresh basil.