Step 1

Melt the butter in an ovenproof 10-inch skillet over medium heat. Add the leeks, season with salt and pepper, and cook, stirring, until softened, about 15 minutes. You may need to reduce the heat to keep the leeks from browning too much.

Step 2

In a bowl, whisk the eggs just until well blended. Whisk in the herbs and the Parmesan and season with salt and pepper. Pour the eggs into the skillet and stir to distribute the leeks evenly. Reduce the heat to low. Cook, using a spatula to lift the edges of the egg to allow the uncooked egg to flow underneath, until the edges and bottom of the frittata are set but the center is still moist, 13 to 15 minutes.

Step 3

Preheat the broiler and adjust the oven rack about 6 inches from the heat source. Slide the skillet under the broiler. Broil the frittata until the top is lightly colored and the center is firm, about 1 minute. Using a wide spatula, carefully shimmy the frittata onto a cutting board. Cut it into wedges and serve it at once. Originally published March 26, 2012.