Onion-Potato Frittata

Martha makes a savory frittata with fingerling potatoes, onions, and goat cheese.

Frittata

For the Filling:
- 2 tablespoons olive oil
- 1 medium yellow onion, thinly sliced
- 2 tablespoons unsalted butter
- 1/4 pound small fingerling potatoes, thinly sliced
- Coarse salt and freshly ground pepper
- 4 basil leaves, chopped
- 1 tablespoon chopped flat-leaf parsley
For the Eggs:
- 12 large eggs
- 1/4 cup heavy cream
- Coarse salt and freshly ground pepper
For the Topping:
- 3 ounces fresh goat cheese, cut into 6 pieces
- 2 ounces Parmigiano-Reggiano or Asiago cheese, finely grated (1/2 cup)

Heat 1 tablespoon olive oil in a 10-inch nonstick skillet over medium heat. Cook onion until soft and translucent, stirring occasionally, 3 to 4 minutes. Remove onions and add remaining tablespoon olive oil and 2 tablespoons butter. Add potatoes and season with salt and pepper. Saute until they begin to turn golden brown, about 4 minutes. Return onions to skillet in an even layer. Sprinkle evenly with basil and parsley.
Heat broiler. Use a whisk to lightly beat eggs in a large bowl, then whisk in cream, and season with 1/2 teaspoon salt and 1/8 teaspoon pepper.
Pour egg mixture into skillet. Cook, using a heatproof flexible spatula to stir and push egg from edges to center of pan so runny parts run underneath, until eggs are almost set (they should still be wet on top but otherwise set throughout), 2 to 3 minutes.
Drop dollops of goat cheese on top of frittata, distributing evenly and pressing down into eggs a bit with the spatula. Sprinkle evenly with Parmigiano-Reggiano cheese. Broil until frittata is set on top and has puffed slightly, and cheese is melted and golden, 1 to 1 1/2 minutes.
Gently run the spatula around the edges and underneath the frittata and carefully slide out of pan onto a plate. Slice into six wedges and serve hot, warm, or at room temperature.