Ingredients

1 tablespoon extra-virgin olive oil
1 cup diced leek (white part only)
6 large eggs, preferably pasture-raised
1/2 cup heavy cream
2 tablespoons grated Parmesan cheese
2 teaspoons kosher salt
1/2 teaspoon finely ground black pepper
2 teaspoons chopped fresh oregano, or 1 teaspoon dried Sicilian oregano
1/2 cup roasted onions
4 ciabatta rolls
8 slices white Cheddar cheese
8 tablespoons roasted tomatoes

Directions

1. Preheat the oven to 300 degrees Fahrenheit.
2. In a 10-inch ovenproof skillet, heat the oil and saute the leek over low heat until soft but without color. In a large bowl, crack and whip the eggs and add the cream, Parmesan cheese, salt, pepper, and oregano. Add the leek and the onions.
3. Pour the egg mixture back into the skillet and place in the oven. Bake the frittata for about 30 minutes, until the center is set. Use immediately or allow to cool (keeps in fridge for about 1 day).
4. Increase the oven to 350 degrees or preheat if preparation has been delayed.
5. Slice the ciabatta rolls in half and place one slice of Cheddar on each top and bottom slice of bread. Place the bread in the oven and remove once cheese is melted. Simultaneously, reheat the frittata in oven if made ahead of time.
6. Cut the frittata into four pieces and place one piece on each bottom slice of bread. Top with the roasted tomatoes. Close the sandwiches and serve.

Makes 4 sandwiches.