Start by boiling water and adding the rotini pasta until it is just al dente. You will know it is ready when it is slightly firm to the bite. This ensures your pasta will not get mushy later. Keep an eye on it, as overcooking can ruin your dish.
While the pasta cooks, fry the bacon strips in a skillet until they are crispy and browned. The smell of sizzling bacon will fill the kitchen! Once done, let them drain on paper towels, but do not rush and skip this step—it helps keep them crispy.
Use the same skillet to sear the chicken breasts until golden on both sides. You will want them cooked through but still juicy. Searing adds flavor, so do not skip this for bland chicken. Avoid cooking them too long or they will turn dry.
Melt butter in a thick pot and whisk in flour until it is bubbly and golden. Pour in the half and half slowly, whisking continuously until the mixture thickens. The sauce should look creamy and smooth. Make sure to stir constantly to prevent lumps.
Once your sauce is nice and thick, add minced garlic, onion powder, Italian seasoning, and ranch seasoning mix. The aroma of garlic will make your mouth water. This is where the flavor really comes together.
Stir in the drained pasta, cooked chicken, and crumbled bacon into the sauce. Make sure everything is well-coated in the creamy sauce; you do not want dry patches of pasta.
Sprinkle in the shredded cheddar cheese and stir until it melts into the dish. Be patient with the stirring; leaving clumps could mean some bites are not as cheesy as others.
Finally, give it a taste and adjust with salt and pepper as needed. This step is key to finding the right flavor for you.