Source:  Murielle Guiliano, author of The French Women Don’t Get Fat Cookbook (Atria Cookbooks, 2010).

Serves 4

INGREDIENTS

6 eggs
1 teaspoon grainy mustard
Pinch of red pepper flakes
Salt and freshly ground pepper
2 tablespoons unsalted butter
1 tablespoon olive oil
1 leek, white part only, rinsed and thinly sliced
4 ounces baked ham, cut into small pieces

PREPARATION

1. Preheat the broiler.
   
   
2. In a medium bowl, whisk together the eggs, mustard, and pepper flakes and season with salt and pepper.
   
   
3. Heat the butter and olive oil in a large nonstick oven-safe skillet over medium heat until the butter has melted. Add the leek and cook, stirring, until softened, 3 to 4 minutes. Add the ham and cook, stirring, until warm, about 2 minutes.
   
   
4. Add the egg mixture and swirl the skillet to distribute the eggs and filling evenly over the surface. Shake the skillet gently, tilting slightly while lifting the edges of the frittata with a spatula to let the raw egg run underneath for the first 1 to 2 minutes.
   
   
5. Cook until the eggs are almost set, about 5 minutes total, and place the skillet under the broiler (not too close) for 1 minute. The frittata will puff up and brown slightly. Remove from the oven and carefully slide the frittata out of the skillet using a spatula. Cut into wedges and serve hot, at room temperature, or cold. Note: If desired, sprinkle 1/2 cup grated Gruyère on top of the frittata just before placing under the broiler.