Prep: 1. Boil water for pasta. 2. Slice and rinse leeks. Finely chop garlic. 3. Grate cheese. Make: 1. Cook the pasta according to package directions. (When it's done, reserve 1/4 cup cooking liquid, drain the pasta and return it to the pot.) 2. Meanwhile, heat the oil in a large skillet over medium-low heat. Add the leeks, salt and pepper to taste and cook, stirring occasionally for 6 to 8 minutes. 3. Stir in the garlic and cook for 1 minute. 4. Whisk in the milk and bring to a simmer. Whisk in the cream cheese, Parmesan and nutmeg. 5. Once cheese is melted, stir in the peas and simmer, stirring occasionally, until slightly thickened, 2 to 3 minutes. 6. Toss the pasta with the cream sauce, adding some of the reserved cooking liquid if the pasta seems dry.
You can stretch this a little further by adding leftover meat (ham and chicken work great) or extra veggies.