Heat oven to 350 degrees. In heavy-bottomed, ovenproof saucepan over medium-high heat, cook sausage until browned and done through. Remove to a plate with a slotted spoon, discarding all but 2 tablespoons fat.
Saute carrots, celery, and onions about 5 minutes. Add red pepper flakes and half of rosemary, crumbling with fingers, and cook 1 minute. Add Marsala and red wines, stirring and scraping any browned bits from the bottom. Cook on high heat until liquid has reduced by half.
Add sausage back to pan. Add beef broth and tomatoes and cook until reduced by half. Stir in cheese and remaining rosemary. Turn heat off and add stir in half & half. Season with salt and pepper. Stir in fresh, uncooked gnocchi and bake 1 hour. Garnish with dried celery leaves or fresh parsley.