Clarence Court Burford Brown eggs have a deep-coloured yolk and are perfect for a rich dish like this. You could also use chicken or duck livers instead of kidneys.
2 medium-sized baking potatoes, parboiled in their skins for about 15 minutes, then left to cool
1 small onion, peeled and thinly sliced
2-3tbsp vegetable or corn oil
1 medium shallot, peeled, thinly sliced
4 lambs' kidneys, cut into rough 1cm dice
A good pinch of cayenne pepper
A good knob of butter
Salt and freshly ground white pepper
4 Burford Brown eggs
Remove the skins from the potatoes and grate the flesh on the coarse side of a grater. Mix with the sliced onion in a bowl; season. Heat some vegetable oil in a small, non-stick frying pan. Divide the potato mix into four and place in the pan, shaping into thin patties with the help of a spatula. Cook them for 4-5 minutes on each side until crisp, then remove from the pan and keep warm.
Season the kidneys with salt, pepper and cayenne pepper. Heat a little vegetable oil in a frying pan and fry the shallots for 30 seconds; add the kidneys and cook on a high heat for another 30 seconds; add the butter and 1tbsp of water to form a sauce just coating the kidneys. Fry the eggs in a little vegetable oil and butter, place the rosti on warmed serving plates with the egg on top and spoon the kidneys around.