Cook the penne pasta in a pot of salted water until al dente according to package instructions. Keep some of the pasta water for the sauce then drain the pasta and cover to keep warm.

Coat the shrimp with 1 Tbsp of the cajun seasoning. In a deep skillet, heat 1 Tbsp oil over medium heat. Once hot, add the seasoned shrimp in a single layer and saute for about 1-2 minutes per side, or until the shrimp is no longer translucent, remove from skillet and cover to keep warm.

In the same skillet, melt 2 Tbsp butter with the minced garlic and cook 30 seconds until fragrant. Add in the diced tomatoes and saute for about 2-3 minutes.

Pour in the heavy whipping cream, remaining 1 Tbsp cajun seasoning and grated parmesan cheese. Bring to a simmer then reduce to medium/low heat and continue 2-3 minutes or until the sauce thickens.

Add the shrimp and pasta back into the skillet and stir until the noodles are coated in sauce and everything is heated through. If needed, add a splash of the reserved pasta water to thin the sauce. To serve, garnish with more parmesan and chopped parsley, if desired.