Preheat your oven to 200°C/400°F/gas 6. Place the squash on a baking tray, drizzle with olive oil and pop in the hot oven for around 15 minutes, or until tender.
Pour a couple of lugs of olive oil into a large frying pan, add the garlic and basil stalks and fry for a couple of minutes. Add your tomatoes to the pan, breaking them up with a wooden spoon and bring to the boil. Drop in the roasted squash, bring to the boil, then simmer for 10 minutes.
Meanwhile, bring a large pot of salted water to the boil, add the penne and cook for a couple of minutes less than it says on the packet. Drain, then toss with the sauce.
Tear up the basil leaves and sprinkle into the pan with some salt and pepper. Stir in the ricotta and the stock, then bring back to the boil.
Rub a large baking tray, ovenproof pan or earthenware dish with olive oil and spoon in all the pasta and sauce. Tear over the ball of mozzarella and top with the Parmesan. Rub the sage leaves with a little olive oil and put on top.
Pop it into the preheated oven and bake for 15 minutes or until golden and bubbling. Serve with a crisp green salad.
Tip: If you're a chilli freak like me, try adding a chopped fresh chilli to your tomato sauce.