Roughly chop zucchini and onion and process mushrooms, zucchini and onion in a food processor until finely chopped.
Melt butter in a large skillet over medium heat. Stir in garlic and chopped vegetables. Reduce heat, cover and simmer 20 minutes, until tender and juicy.
Meanwhile, bring a large pot of lightly salted water to a boil. Add pasta and cook for 8 to 10 minutes or until al dente; drain.
Stir flour into vegetables. Stir in cream or milk and season to taste. Let simmer 10 minutes more, then toss with cooked pasta.
