From The New Best Recipe (p. 637): "The method for cooking the frittata fell into three camps: cooking the frittata fully on the stovetop, cooking the frittata fully in the oven, and starting the frittata on the stovetop and then finishing it in the oven. We first tried cooking the frittata fully on the stovetop, but no matter what we did, the underside always ended up tough and overcooked. Cooking the frittata fully in the oven proved problematic as well. We tried cooking at different temperatures and lengths of time, but the results were either too dry or unevenly cooked. A combination of the two turned out to work the best. Using this method, we cooked the frittata almost fully on the top of the stove and then placed it in the oven to finish cooking the top. The resulting frittata was evenly cooked and firm without being too dry—exactly what we had been seeking."