Prepare the Spice Mix and Pasta: In a small bowl, combine all the ingredients for the Cajun spice mix and set aside. Bring a large pot of salted water to a rolling boil. Add the linguine and cook according to the package directions until al dente. Just before draining, reserve about 250ml (a mugful) of the starchy pasta water.

Sauté the Vegetables: While the pasta is cooking, heat the olive oil and butter in a large, deep frying pan or sauté pan over a medium heat. Once the butter is melted and foaming, add the diced onion and red pepper. Cook for 6-8 minutes, stirring occasionally, until softened and lightly caramelised.

Add Aromatics: Add the minced garlic to the pan and cook for another minute until fragrant, being careful not to let it burn. This is a quick step, but it builds a crucial layer of flavour.

Bloom the Spices: Sprinkle the prepared Cajun spice mix over the vegetables. Stir continuously for 30-60 seconds. I find that this step, known as 'blooming', is essential as it toasts the spices in the hot fat, deepening their flavour and unlocking their full aroma.

Create the Creamy Sauce: Pour in the double cream, stirring to combine everything. Bring the sauce to a gentle simmer, then reduce the heat to low. Let it bubble away gently for 2-3 minutes to thicken slightly. Stir in the grated Parmesan cheese until it melts and the sauce becomes smooth and glossy.

Cook the Prawns: Add the raw prawns to the sauce. Let them cook for 2-3 minutes, turning them halfway through, just until they turn pink and opaque. Be careful not to overcook them, or they will become tough.

Combine and Finish: Drain the cooked pasta and add it directly to the pan with the sauce and prawns. Add a good splash (about 100ml) of the reserved pasta water. Toss everything together vigorously for a minute until the sauce clings beautifully to every strand of pasta. If it seems too thick, add another splash of pasta water until you reach your desired consistency.

Serve Immediately: Stir through the sliced spring onions and chopped parsley. Divide the Cajun shrimp pasta among warm bowls, and finish with an extra grating of Parmesan cheese and a crack of black pepper.