Creamy Chicken Pasta Soup

Melt butter in a large heavy pot over medium heat. Add mushrooms, celery, carrots and onion. Cook until celery and onion are tender, about 5 minutes. Add flour and cook 3 minutes, stirring frequently. Gradually mix in chicken stock. Bring soup to a simmer, stirring frequently. Add half and half and chopped parsley and simmer 5 minutes. Add chicken and simmer until cooked through, about 5 minutes. (May be prepared ahead to here.)

Cook penne pasta in a large pot of boiling salted water until just tender, but still firm to bite. Drain pasta. Bring soup to a simmer. Mix in cooked pasta and snap peas and simmer 2 minutes. Mix in lemon juice and season to taste with salt and pepper.