Bring a large pot of salted water to a boil and cook the penne according to package directions. Drain it about one minute before it's completely tender (it'll finish cooking in the sauce later). Set the cooked pasta aside for now.

Heat the olive oil in a large skillet over medium-high heat. Add the diced onion and cook for about 2 minutes until it softens and gets translucent. You'll see it change color pretty quickly.

Stir in the minced garlic and sliced bell pepper, cooking for another 2 minutes until everything smells amazing. Don't walk away during this part—garlic burns fast and tastes bitter. I learned that the hard way years ago.

Add the shrimp to the skillet and sprinkle with Cajun seasoning, salt, and pepper. Cook for about 3 minutes per side until the shrimp turns pink and opaque. They cook super fast, so keep an eye on them.

Pour in the chicken broth and scrape up any browned bits stuck to the bottom—that's pure flavor. Let it simmer for one minute to reduce slightly. Next, add the heavy cream and stir everything together gently.

Reduce heat to medium and stir in the shredded mozzarella until it melts into the sauce. Add the cooked penne and frozen peas, tossing everything until well combined. The creamy cajun shrimp pasta family dinner should look creamy and saucy, not dry.

Taste and adjust seasoning if needed—I always add a tiny pinch more Cajun seasoning because I like it bolder. Sprinkle fresh parsley on top right before serving. That green adds a fresh pop that balances all the richness.