There are three choices to finish cooking the frittata.

The simplest is to use the oven.

Preheat the oven while you start the cooking, then put the frittata right in the pan into the hot oven where it firms up, cooks through, and makes a nice crust.

A frittata finished in the oven can be cooked to a lesser degree on top of the stove. Once the bottom and sides have begun to set, it can be allowed to finished cooking through in the oven without any further fussing on your part.

The second method is to use the broiler.

Cook the frittata a bit longer on the stovetop, until the dish is fairly close to being done, then put the frittata under the broiler. where the top will set and form a nicely browned crust. This involves a little more of the cook's attention so as not to burn the top.

The final choice is a little trickier, but not difficult.

Cook the frittata until the sides and bottom are well set, and the center has begun to firm up. Run a knife around the sides of the pan to loosen the edges. Place a serving platter or plate large enough to cover the sauté pan upside down over the top of the pan. Hold the panhandle in one hand. With the other hand, press the platter down firmly against the pan and flip the whole thing over! Remove the pan.

The frittata is now upside down on the platter. Slide it off the platter back into the pan and continue cooking until the bottom (once the top) is set. This may sound difficult but is actually an easy process.

What method to choose? Only occasionally do I use the broiler - perhaps if the oven is already in use or I want a particularly browned top. The stovetop method is my choice on hot summer days when heating the oven is not desirable.

My preference is to finish the frittata in the oven. It is easy, almost full proof and makes for a nice interior and good crust. It allows me to attend to other things like making a salad or setting the table while the frittata cooks.