Definition of Frittata, courtesy of Wikipedia:
A frittata is a type of Italian omelette that frequently features fillings such as meats, cheeses, and vegetables. Like a normal omelette, a frittata is prepared in a skillet. However, whereas a normal omelette is cooked on a stovetop and served folded, a frittata is first partially cooked on a stovetop but then finished under the grill (broiler) and served open faced.
Here is the recipe for one of my favorite frittatas-
Spinach and Cheese Frittata
1/2 lb fresh spinach, chopped (or 10 oz pkg frozen, thawed and squeezed dry)
3 Tbl extra-virgin olive oil
3 Tbl butter
8 large eggs
1 cup freshly shredded mozzarella cheese
1/2 tsp grated nutmeg
1/2 tsp dried thyme
salt and pepper to taste
In large skillet, saute spinach in olive oil and butter, about 4 minutes.
In medium bowl, beat eggs till frothy, then stir in cheese, nutmeg, thyme, salt and pepper. Pour mixture evenly into skillet and shake skillet to cover bottom evenly. Heat over medium heat.
When bottom is formed and browned, put large heatproof plate over skillet, flip, and slide frittata back into skillet to cook top, or leave in skillet, (make sure handle is heatproof!) and place under broiler to brown top.