Cook the tortellini as per package directions, drain reserving 3 tablespoons cooking liquid.
Place the sausages in boiling water and cook until firm, remove and cool until cool enough to handle. Thinly slice the sausage.
Over medium heat, melt the butter and add olive oil, cook sausages through until nicely browned; stir in onions, minced garlic and cabbage.
Saute for 5 minutes or until cabbage is crisp tender; stir in drained cooked tortellini, fennel seeds, red pepper flakes and pimentos. Season with salt and lots of freshly ground black pepper to taste.
Lower the heat to low, add the crème fraiche and reserved pasta cooking liquid; cook just until warmed through.
Serve with freshly grated Parmesan cheese and crusty Italian bread.