1. Bring a large pot of salted water to a boil and cook the pasta until al dente according to package directions. Reserve about 1 cup of the pasta water, then drain and set the pasta aside.

2. Heat the butter and olive oil in a large skillet over medium-high heat. Once melted, add the chopped onion and cook for 2–3 minutes, stirring often, until soft and translucent.

3. Add the chicken pieces to the skillet. Season with black pepper and 1 tablespoon of the ranch seasoning. Cook, stirring occasionally, until the chicken is cooked through and no longer pink, about 5–6 minutes.

4. Stir in the garlic and cook for about 30 seconds, just until fragrant.

5. Pour in the half-and-half along with ½ cup of water or pasta water. Add the remaining ranch seasoning, smoked paprika, and red pepper flakes. Stir well and bring the sauce to a gentle simmer. Let it cook for 2–3 minutes until slightly thickened.

6. Reduce the heat to low and add the cheddar and Parmesan cheeses. Stir until the cheese is fully melted and the sauce is smooth and creamy. Taste and adjust with salt as needed.

7. Add the cooked pasta to the skillet and toss until evenly coated in the sauce. If the sauce is too thick, add a little more reserved pasta water until you reach your desired consistency.

8. Serve immediately while hot.