We wanted an easy, supersavory red sauce supper packed with the flavors of Italian sausage. To get there, we began by quickly sautéing some chopped fresh fennel (to complement the fennel seed in the sausage), onion, garlic, and tomato paste on the stove. Then we simply added that mixture to the slow cooker along with the superflavorful additions of raw hot Italian sausage, crushed tomatoes, tomato sauce, and red wine. After the ragu simmered away unattended all day, the flavors melded beautifully and the sausage was tender enough to break up with a potato masher.