Prepare your ingredients: Peel and devein 14 shrimp if not already done. Mince 1 tbsp garlic finely. Finely dice 1/3 cup onion and chop 1/3 cup red bell pepper into small, even pieces. Measure out all spices into a small bowl so they're ready to add all at once.
Cook the pasta: Boil a large pot of well-salted water. Cook 140g pasta until just al dente according to packet instructions. Before draining, scoop out at least 1/2 cup of pasta water and set aside. Drain the pasta and set aside.
Season and sear the shrimp: Pat shrimp thoroughly dry with paper towel. Season both sides with 1/2 tsp salt, 1/2 tsp black pepper, and 1 tsp Cajun seasoning. Heat 2 tbsp olive oil in a large pan over medium-high heat. Sear shrimp in a single layer for 1–1.5 minutes per side until pink and curled into a loose C shape. Remove immediately and set aside.
Sauté the aromatics: In the same pan, add the remaining 1 tbsp olive oil over medium heat. Add 1/3 cup onion, 1/3 cup red bell pepper, and 1 tbsp garlic. Sauté for about 2 minutes, stirring occasionally, until fragrant and softened. Don't let the garlic burn.
Add the spices: Add 1/2 tsp smoked paprika, 1/2 tsp chilli flakes, 1/2 tsp Cajun seasoning, 1/4 tsp cayenne pepper, 1/2 tsp dried parsley, and 1/2 tsp salt. Stir well and cook for 60 seconds, stirring constantly, to bloom the spices.
Build the cream sauce: Pour in 1/2 cup thickened cream and stir to combine. Bring to a gentle simmer over medium heat and cook for 2–3 minutes until slightly thickened and the sauce coats the back of a spoon. Taste and adjust seasoning.
Bring it all together: Add the cooked pasta and shrimps. Toss well to coat. Add reserved pasta water gradually, a splash at a time, tossing and assessing consistency until the sauce is creamy and glossy.
Garnish and serve: Divide between bowls. Finish with a pinch of chilli flakes and dried parsley. Serve immediately.