Cook the Potatoes: Place the peeled and chunked potatoes in a large saucepan and cover with cold, salted water. Bring to the boil and cook for 15-20 minutes, or until the potatoes are completely tender when pierced with a knife.

Prepare the Chicken: While the potatoes are cooking, pat the chicken breasts dry with a paper towel. Season both sides generously with salt and pepper.

Sear the Chicken: Heat the olive oil in a large, heavy-based frying pan or skillet over a medium-high heat. Add the chicken breasts, ensuring not to overcrowd the pan (cook in two batches if necessary). Cook for 6-8 minutes on each side, until golden brown and cooked through (the internal temperature should be 74°C). Remove the chicken from the pan and set aside on a plate to rest.

Mash the Potatoes: Once tender, drain the potatoes thoroughly and return them to the hot, dry pan for a minute to steam off any excess moisture. I used to struggle with watery mash until I discovered this technique. Mash them until smooth, then add the room temperature butter, warm milk, salt, white pepper, and nutmeg. Beat with a wooden spoon until light and fluffy. Cover and keep warm.

Start the Sauce: Reduce the heat under the chicken pan to medium. Add the 25g of butter and the finely chopped onion. Cook for 4-5 minutes, stirring often and scraping up any browned bits from the bottom of the pan, until the onion is soft and translucent.

Build the Flavours: Add the minced garlic and thyme leaves and cook for another minute until fragrant. Pour in the white wine to deglaze the pan, continuing to scrape the bottom. Let the wine bubble and reduce by about half, which should take 2-3 minutes.

Create the Creamy Sauce: Pour in the chicken stock and bring to a simmer. Let it bubble gently for about 5 minutes to reduce slightly and intensify in flavour. Reduce the heat to low and stir in the double cream.

Finish and Serve: Return the rested chicken breasts (and any juices from the plate) to the pan with the sauce. Let them warm through gently for a minute or two. Season the sauce with salt and pepper to your taste. Serve the chicken immediately with a generous helping of the creamy mashed potatoes, spooning plenty of the sauce over everything. Garnish with fresh parsley if you like.