Bring large pot of salted water to boil. Add spaghetti and cook until al dente. While pasta is cooking, snap woody bottoms off asparagus and slice into 1/4 inch pieces. Add to the cooking pasta during the last 3 minutes of cooking. Drain all together and set aside.
Return pot to medium heat and melt butter. Sauté butter and zucchini with salt and pepper to soften, 4 minutes. Sprinkle flour over top and stir. Cook 1 minute.
Pour in chicken stock and bring to boil to thicken. Reduce heat to medium low and stir in cream cheese, parmesan cheese, more salt and pepper, basil, lemon zest and peas.
Cook 5 minutes, then toss in cooked pasta and asparagus. Divide between serving dishes and top with more parmesan cheese. Serve immediately.