Cook the pasta in large saucepan of boiling salted water for 5-7 minutes (half the time recommended on the packet). Drain and set aside.
Meanwhile, heat oil in a large frying pan over medium heat. Add onions and paprika and cook for 8 minutes, stirring often, until soft. Add chorizo, increase heat and cook for 5 minutes. Add half the tomatoes and cook for 3 minutes until they start to soften. Remove from the heat.
Preheat oven to 200°C fan-forced. Lightly oil a baking dish, add pasta and fill with tomato mixture. Crumble over the ricotta and drizzle with stock. Cover and bake for 15 minutes or until pasta is tender. Remove from the oven, sprinkle with parmesan and parsley and serve.