Cook the pasta following the instructions on the package. Drain and set it aside.
If your shrimp is frozen. make sure it's defrosted. You can run it under cold running tap water for 10 minutes.
Add the shrimp and cajun seasoning to a bowl and toss to coat evenly.
In a large skillet over medium-high heat, heat 1 tablespoon of olive oil. Sear the shrimp for about 2 minutes per side. Transfer to a plate.
Add the remaining olive oil to the same pan. Reduce the heat to medium and sauté the onion and garlic for 3–4 minutes until soft. Stir in the tomato paste and cook for about 30 seconds.
Pour in the heavy cream and bring the mixture to a boil. Lower the heat and simmer for 2 minutes.
Add the shrimp and cooked pasta to the pan. Stir everything together and cook until heated through.
Take off the heat, mix in the Parmesan, and serve hot.
Nutrition information is calculated using an ingredient database and should be considered an estimate.