Preheat the oven to 200C/400F/Gas 6.
For the fondant potatoes, place the fondant potatoes ingredients into a lidded saucepan and season, to taste, with salt and freshly ground black pepper. Bring to the boil, then reduce the heat until the mixture is simmering. Cover and simmer for 10-12 minutes, or until tender. Drain off any excess liquid.
For the lamb chops, sprinkle the ground mustard seeds and coriander seeds onto a plate. Dredge the lamb chop in the spices and season, to taste, with salt and freshly ground black pepper.
Place the coated lamb chop onto a baking tray and transfer to the oven for 6-8 minutes (for medium), or until cooked to your liking.
To serve, spoon the fondant potatoes onto a serving plate and top with the lamb chop.
