Presoak a clay pot, top and bottom, in water for 15 minutes.
Combine the flour, salt, pepper, and herbs in a paper bag and mix thoroughly. Add the cubed lamb and shake. Set aside any remaining flour mixture.
In a frying pan, brown the lamb well on all sides in the butter and lard, then put in the presoaked pot. Put the leeks, carrots, and mushrooms in the frying pan along with t