Bring a large pot of salted water to a rolling boil. Add rotini pasta and cook according to package instructions, usually about 8–10 minutes, until al dente. Reserve a cup of pasta water, then drain.

In a large skillet, heat a tablespoon of oil over medium-high heat. Add diced skinless boneless chicken breasts and sauté for 5–7 minutes until golden and cooked through. Remove and set aside.

In the same skillet, lower the heat and add minced garlic. Sauté for 1–2 minutes until fragrant.

Reduce heat to low, pour in heavy cream, and stir. Gradually add mozzarella and Parmesan cheese until melted and smooth.

Sprinkle in Cajun seasoning and stir until mixed. Adjust seasoning to taste.

Add cooked rotini and chicken back into the skillet and toss for 2–3 minutes, adding reserved pasta water as needed.

Remove from heat and serve hot, garnished with fresh herbs if desired.