Slice sausages 1/2" thick. Using a large saucepan, brown sausages. (If turkey, spray pan first with vegetable spray.) Pour off any fat. Add celery, zucchini and onion. Saute 2 minutes, stirring. Put stock, tomato sauce and basil into crockery pot and mix. Heat on high (300) for 30 minutes. Add sausage-vegetable mixture to crockery pot. Turn to low and cook 2-3 hours. Salt and pepper to taste. Ladle into bowls and garnish with grated cheese. Serve this hearty soup accompanied by garlic-buttered toasted French bread. Italian sausages made of turkey meat can be substituted, and make this a perfect low fat meal.
From "Extra-Special Crockery Pot Recipes"