1Bring a large pot of salted water to a boil. Add rigatoni and cook according to package directions until al dente. Reserve 120ml (1/2 cup) pasta water, then drain.
2Heat olive oil in a large skillet over medium-high heat. Add chorizo slices and cook for 2-3 minutes until crispy. Add prawns, season with half the Cajun seasoning, and cook for 2-3 minutes per side until pink and opaque. Remove and set aside.
3In the same skillet over medium heat, add minced garlic and remaining Cajun seasoning. Sauté for 30 seconds, then pour in chicken broth and bring to a simmer for 2 minutes.
4Reduce heat to medium-low and stir in heavy cream. Let simmer for 3-4 minutes until sauce begins to thicken. Add Parmesan cheese and stir until melted and smooth.
5Add fresh spinach and cook for 1 minute until wilted. Return prawns and chorizo to the pan, then add cooked pasta. Toss to coat, adding reserved pasta water if needed to loosen the sauce.
6Divide into bowls and top with extra Parmesan cheese and black pepper. Serve immediately for the best creamy, spicy flavor with perfectly coated pasta.