Cook the Pasta: Bring a large pot of well-salted water to a boil. Add the rigatoni and cook according to package directions until al dente. Just before draining, reserve about 250ml (a cup) of the starchy pasta water. Drain the rigatoni.

Sear the Chicken: While the pasta cooks, pat the diced chicken dry with a paper towel and season generously with salt and pepper. Heat the olive oil in a large, heavy-bottomed frying pan or skillet over a medium-high heat. Add the chicken in a single layer (work in batches if necessary to avoid overcrowding) and cook for 3-4 minutes per side, until golden brown and cooked through. Remove the chicken from the pan and set aside on a plate.

Build the Sauce Base: Reduce the heat to medium-low. Add the butter to the same pan. Once it has melted and is foaming, add the minced garlic and cook for 1-2 minutes, stirring constantly, until it's fragrant. Be careful not to let it brown or it will taste bitter.

Deglaze the Pan: Pour in the white wine (or chicken stock) to deglaze the pan, scraping up any browned bits from the bottom with a wooden spoon. Let it bubble and reduce by about half, which should take 2-3 minutes.

Make it Creamy: Stir in the double cream and lemon juice. Bring the sauce to a gentle simmer and let it cook for 2-3 minutes to thicken slightly. Season with a little more salt and pepper to taste.

Combine Everything: Return the cooked chicken and any accumulated juices to the pan. Add the drained rigatoni and about 120ml (1/2 cup) of the reserved pasta water. I find that starting with this amount is best; you can always add more.

Finish the Dish: Stir everything together over a low heat for about a minute until the pasta is well-coated in the sauce. The starch from the pasta water will help the sauce emulsify and cling to the rigatoni. If it looks too thick, add another splash of pasta water.

Add Cheese and Herbs: Remove the pan from the heat. Stir in the grated Parmesan cheese and the chopped fresh parsley. The residual heat will melt the cheese into a gloriously smooth sauce.

Serve Immediately: Divide the Garlic Butter Chicken Rigatoni among warm bowls and top with an extra grating of Parmesan cheese and a sprinkle of black pepper.