Pasta with Bolognese Sauce

 I got this recipe from Costco cookbook. Costco cookbooks has a lot of great recipes.
 http://www.costcoconnection.com/connection/2008cookbook/#pg108

Ingredients
1 medium onion

4 garlic cloves
2 tablespoon olive oil
Nonstick cooking spray
3 carrots
2 celery stalk
1 pound ground turkey
Salt and pepper
2 can crushed tomatoes
1 cup reduced fat low sodium chicken stock
1 tablespoon sugar
1/2 cup sweet potato puree
2 tablespoons grated Parmesan cheese
1 package whole wheat spaghetti

Preparation Method
Put onion and garlic in a food processor and finely chop or chop by hand.
Coat a large nonstick skillet with cooking spray and set over medium heat.
When the skillet is hot, add olive oil, then onion and garlic, cook until onion and garlic begin to soften, 2-3 minutes.
Add ground turkey and break small chunks with a wooden spoon. Add salt and pepper and cook until the meat begin s to brown 3-4 minutes.
Put carrots and celery in the food processor and finely chop; add to the skillet and cook 3-4 minutes.
Add tomatoes, broth and sugar. Reduce the heat to low, cover and simmer, stirring occasionally,  for 30 minutes. stir in sweet potato puree and parmesan.
Cook pasta in a large pot of salted boiling water according to package directions until dante. Pour the warm sauce over the paste.