Enzo's Spaghetti alla Carbonara

Yield: 1 serving

4 ounces spaghetti
1/2 cup olive oil
2 large tablespoons coarsely chopped onion
2 strips bacon, cut into 1-inch lengths
1 teaspoon black pepper
1 egg yolk, lightly beaten
1/4 cup combined Romano and Parmesan cheeses

In a skillet, saut