1. Fill the saucepan with 3 quarts of cold water. Bring the water to a boil, and add 1 tablespoon of salt. Add the pasta, and boil on medium heat, stirring occasionally. Test the pasta 1 to 2 minutes before the packaging says it should be ready; you want the pasta to be cooked al dente because it will absorb extra liquid from the sauce. Reserve 3/4 cup of the pasta water before you drain the pasta.

2. While the pasta cooks, prepare the sauce. Slice the light-green part of the leek into thin rounds. Snap the tough ends off the asparagus, and cut the spears into 1-inch pieces.

3. Heat the olive oil in the sauté pan over medium-high heat. Add the leeks, the asparagus, and a pinch of salt. Sauté the vegetables for about 3 minutes or until the leeks start to caramelize.

4. Add the peas and lemon zest. Sauté for one more minute. Reduce the heat to medium.

5. Add the reserved pasta water and cream to the sauté pan. Bring the sauce to a simmer (you may need to turn up the heat a bit), and allow it to thicken for about 30 seconds. Turn the heat off, and add the lemon juice. Sprinkle the Parmesan cheese over the sauce, stirring as you add it so it melts evenly and is evenly distributed throughout.v

6. Add the hot pasta to the sauce, and stir well to combine. Top with fresh parsley and ground pepper to taste. Serve immediately with extra Parmesan if desired.