Serves 2-3; can be multiplied.
2 tsp olive oil
1 small onion, cut in half, thinly sliced
3 small red-skinned new potatoes, thinly sliced
6 large eggs
2 Tbsp blue cheese, crumbled
2 tsp milk (nonfat or low-fat)
2 Tbsp chopped fresh flat-leaf parsley
1/4 tsp kosher salt
1/4 tsp fresh black pepper
2 Tbsp grated Parmigiano-Reggiano cheese, or more to taste
In a small nonstick frying pan (I use an 8-inch pan), heat the oil over medium heat. Sauté the onions and potatoes for 3-4 minutes, until gently browned.
While the vegetables are browning, beat the eggs in a large glass measuring cup. Stir in the blue cheese and milk. Then add the parsley, salt and pepper.
When the onions and potatoes are lightly browned, turn the heat to low. Pour the egg mixture over the top, and swirl the pan a bit to get the eggs evenly distributed.
Cover the pan and cook on low for 3 minutes. Lift the cover and, with a rubber spatula, lift the edges of the frittata to let some of the uncooked egg flow underneath. Cover and cook for 3 more minutes, and repeat the lifting/flowing.
Preheat your broiler.
Cook covered, for 3-4 minutes more, or until the frittata is almost completely set but the top is a little bit runny.
Remove the pan from heat, and sprinkle with the parmesan cheese. Place the pan under the broiler until the cheese is bubbling and melted; how long that takes will depend on the type of broiler you have. (My infrared broiler took only one minute to melt the cheese.)
Remove the pan from the oven, and let it sit for 5 minutes before cutting into wedges. Serve warm or at room temperature.