Brown ground beef, onion, and sausage in skillet, drain well. While meat is cooking, bring approx. 2 qts of water to a boil, add 1 tsp salt to water with the shredded zucchini and carrots. Cook 5 min. until tender. Drain very well.
After draining meat, add the can of soup and sour cream, let simmer over low heat. When vegetables are done and drained dry, add to meat mixture.
Add melted butter to dry dressing mix and stir well. Place half of dressing in bottom of casserole dish and spread evenly. Pour meat mixture over this and spread evenly. Layer with remainer of dressing mix