Preheat the oven to 200C.
Rub the chicken thighs with the salt, pepper and garlic powder.
Heat the olive oil on the hob in a very large oven proof lidded dish.
When the oil is very hot, put the chicken thighs in, skin side down, and cook for about 5 minutes until browned all over.
While the meat is browning, mix the sauce ingredients in a small bowl and whisk until combined.
Add the potatoes and carrots to the chicken and pour over the honey and mustard sauce. Make sure everything is coated.
Pop into the preheated oven with the lid off for about 45 minutes. (I always use a pan with a lid as if at any point it looks like the dish may be burning and the chicken isn't cooked through yet, I can pop the lid on).
Check that the chicken is cooked through and the potatoes are tender and serve immediately. If either are not fully cooked, pop back in to the oven until they are.