Soak the lentils overnight in two changes of water. Boil in fresh salted water for about 15 minutes, or until tender, drain and keep hot.
Shallow-fry the onion, bacon and carrot in a little butter. Add the lentils, half the stock and a little red wine. Stir in the rest of the butter, in small pieces, to thicken.
In two hot pans shallow-fry the kidney and sweetbreads separately. In the pan in which you cooked the kidney, make the mustard sauce by whisking or stirring together the mustard and cream. Season with salt and pepper. Allow to boil until the sauce has thickened. Check the seasoning and if necessary add a squeeze of lemon juice.
Serve the kidney on a pool of mustard sauce and the sweetbreads on a bed of lentils.
© 1988 Keith Floyd estate. All rights reserved.