Brown the chicken: Heat the olive oil in a large, deep frying pan or skillet over a medium-high flame. Add the chicken chunks in a single layer — you should hear a satisfying sizzle as they hit the pan. Cook for 4-5 minutes, turning once, until the chicken is golden brown on the outside and no longer pink inside. The surface should feel firm to the touch and smell wonderfully savoury. Transfer the chicken to a plate and set aside.

Sweat the aromatics: Reduce the heat to medium and add the butter to the same pan. Once it's melted and bubbling, toss in the diced onion. Stir for 2-3 minutes until the onion turns translucent and soft — you'll notice the raw, sharp smell giving way to a sweet, mellow fragrance. Add the minced garlic and cook for another 30 seconds, just until it becomes fragrant and the colour shifts to a pale gold.

Build the sauce: Pour in the chicken stock and double cream, then add the dried thyme, salt, and pepper. Stir everything together with a wooden spoon, scraping up any browned bits from the bottom of the pan — those little dark flecks are packed with flavour. Bring the mixture to a gentle simmer; you'll see small bubbles breaking the surface, but not a full rolling boil.

Cook the shells: Tip the dry pasta shells into the simmering liquid and stir well to ensure they're all submerged. Cover the pan with a lid and let it cook for 12-14 minutes, stirring once halfway through. The shells will absorb the liquid as they cook, and the sauce will thicken into a creamy, glossy coating. You'll know they're ready when the pasta is tender but still has a slight bite — a texture that holds up well.

Finish with cheese and chicken: Remove the lid and stir in the grated parmesan cheese. Watch as it melts into the sauce, turning it into a rich, velvety blanket around the shells. Return the browned chicken to the pan, along with any juices that have collected on the plate. Stir gently to combine, then let everything heat through for 1-2 minutes. The chicken will have a slight sheen from the sauce, and the aroma of garlic and cheese will fill your kitchen.

Rest and serve: Take the pan off the heat and let it sit for 2-3 minutes. This short rest allows the sauce to settle and the flavours to meld together. Sprinkle the fresh parsley over the top just before serving. The final dish should look creamy, with the shells glistening and the chicken pieces nestled throughout.