Prepare the Base: Place the chopped potatoes and onion at the bottom of your 5-6 quart slow cooker. This creates a bed for the chicken and ensures the potatoes cook through evenly in the liquid.

Season the Chicken: In a medium bowl, toss the chicken chunks with the salt, pepper, oregano, and thyme until they are evenly coated.

Sear the Chicken (Optional but Recommended): Heat the olive oil in a large frying pan over a medium-high heat. Add the chicken and sear for 2-3 minutes on each side, until lightly golden. You don't need to cook it through. What works best for me is doing this in batches to avoid overcrowding the pan. Transfer the seared chicken into the slow cooker on top of the potatoes.

Add Liquids and Garlic: Pour the chicken stock over the chicken and potatoes. Sprinkle the minced garlic evenly over the top.

Slow Cook: Cover the crockpot and cook on LOW for 6-7 hours or on HIGH for 4-5 hours, until the chicken is cooked through and the potatoes are tender when pierced with a fork. It’s important to ensure the chicken is properly cooked; you can check this with a meat thermometer, following guidance from the Food Standards Agency (FSA).

Create the Creamy Sauce: About 20-30 minutes before serving, whisk the double cream and grated Parmesan cheese together in a small bowl. Pour this mixture into the slow cooker.

Thicken the Sauce: In another small bowl, whisk the cornflour and cold water together to form a slurry. Gently stir this into the slow cooker. This will thicken the sauce into a lovely, velvety consistency.

Final Cook and Serve: Replace the lid and continue to cook on HIGH for another 15-20 minutes, or until the sauce has thickened and is bubbling slightly at the edges. Garnish with fresh parsley before serving hot.