2 to 2 1/2 pounds greens (such as chard, beet greens or kale), stemmed and cleaned

3/4 pound small potatoes (such as baby Yukon Gold or new potatoes)

2 tablespoons extra virgin olive oil

1 medium onion, chopped

2 large garlic cloves, minced

1/4 cup chopped flat-leaf parsley

Salt and freshly ground pepper to taste

3 large eggs

3/4 cup low-fat milk

2 ounces Gruyère cheese, grated (1/2 cup, tightly packed)

1 ounce Parmesan, grated (1/4 cup)