• Preheat oven to 350°F. Lightly grease a large baking pan with 1 tablespoon of the oil. Clean the asparagus and break off the tough ends. Peel and thickly slice the onions into rings.

• Peel the potatoes if desired. Thinly slice the potatoes. Slice the prosciutto into thin ribbons. In a large bowl, whip the egg whites with an electric mixer until stiff peaks form.

• Heat the remaining oil to medium temperature in a large frying pan. Add the potatoes, cover, and cook for 3 minutes. Turn the potatoes, cover, and cook for 3 more minutes. Add the onions, stir, and cover. Continue cooking and turning the potatoes every 3 to 5 minutes until tender and lightly browned.

• Meanwhile, blanch the asparagus in boiling water for about 3 minutes, until just tender. Shock in ice water, and drain.

• Place alternating layers of the cooked potatoes, asparagus, and cheese in the prepared baking pan. Pour the egg whites over the top to cover all the ingredients. Sprinkle with black pepper.

• Bake for 15 to 20 minutes, uncovered, until the egg is thoroughly cooked. Serve with the shredded prosciutto over the top.

Preparing Asparagus

The best way to trim the ends of asparagus spears is to gently hold each end of the spear and bend until the spear breaks. Just don't throw away the ends. You can freeze the “woody” ends for later use in vegetable stock.