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.