Heat a large, wide frying pan, then crumble in the sausage meat and fennel seeds (there’s no need to add any oil). Fry for a few mins until golden and the fat is released, stirring well to break up the meat. Add the mushrooms and fry for a few mins until beginning to soften. Stir in the wine now, if using, bubble for 1 min, then add the tomato sauce and heat through until bubbling.
Meanwhile, boil the penne. When ready, drain and tip into the sauce. Mix well until completely coated, then divide between four plates, finishing with a little parmesan.