If you're using frozen shrimp, place them under cold running water for about 10-15 minutes until they're fully thawed.

Bring a large pot of salted water to a rolling boil over high heat. Add in the penne pasta and cook according to the package instructions, typically around 10-12 minutes, until al dente. Reserve 1 cup of the pasta water before draining.

Season the thawed shrimp with half of the Cajun seasoning, tossing to evenly coat. In a deep skillet, heat 2 tablespoons of olive oil over medium heat. Add the shrimp and cook for 1-2 minutes per side until pink and opaque. Remove the shrimp from the skillet and keep warm.

In the same skillet, melt 2 tablespoons of unsalted butter over medium heat. Add 3-4 cloves of minced garlic and the remaining Cajun seasoning. Sauté for about 1 minute or until the garlic is fragrant and golden.

Stir in one can of diced tomatoes, cooking for an additional 1-2 minutes. Allow to bubble lightly and reduce heat to medium-low.

Gradually pour in 1 cup of heavy whipping cream while stirring continuously. Add 1 cup of grated Parmesan cheese, mixing until melted, about 3-4 minutes. If it's too thick, stir in some reserved pasta water.

Return the cooked shrimp to the skillet along with the drained penne pasta. Toss until well coated in the sauce.

Sprinkle additional grated Parmesan cheese and chopped parsley over the pasta before serving. Plate up and enjoy your cozy, creamy dish!