Greek Frittata

Preheat the toaster to 350° F. In a 2-quart baking dish, add the butter and place in the oven for 5 minutes. Meanwhile, in a large bowl, whisk together the eggs, salt and pepper. Add the spinach, tomatoes, and green onions and toss to combine. Gently stir in the feta. Remove the casserole from the oven. Pour the egg mixture into the casserole dish. Bake until the frittata is lightly browned around the edges and the knife comes out clean, 25 to 30 minutes.