Heat oven to 180C/160C fan/gas 4.
Heat a small roasting tin, and coat the
lamb with 1 tbsp of the oil and some sea
salt. Place the lamb, skin-side down, in
the tin until the fat has turned brown,
then sear all over. Transfer to a plate.
Add the onion to the tin and cook
for about 10 mins until soft. Stir in the
potatoes, thyme, garlic and stock,
and press down with a spoon. Put the
lamb on top and roast in the oven for
25-30 mins until the potatoes are tender
and the lamb cooked to your liking.
Leave to rest under some foil for
about 10 mins. Slice the lamb into
cutlets and scatter with the reserved
thyme sprigs. Serve with a spoonful of
the potatoes and some simply cooked
asparagus, if you like.