Mix the mustard, calvados, oil, pepper, juniper and thyme into a marinade. Make a diamond-shaped cut into the bacon of the leg and rub the marinade completely over the leg. Leave to marinate in the refrigerator for at least 6 hours.
Salt the leg and bake in a casserole for about 2 hours at 200 degrees, depending on the size of the leg. Gradually add the cider in between. Strain the sauce, thicken with the flour or the grated potato and stir in the dash of cream or soy cream.
Fresh spaetzle or potato dumplings, broccoli with almonds, glazed carrots or chestnuts also taste great.