Using a food processor, grind all the meat seasoning ingredients into a paste. Rub the seasoning paste over the surface of the meat after pricking it with a fork.
Wrap the meat in foil and let marinade while you prepare the clay.
Combine the dry ingredients for the baker's clay.
Add liquid in small amounts until dough holds together and can be gathered into a ball.
Roll the dough out to a measure of 20 x 18 inches. Arrange roast in the center of dough and fold dough over the roast. Seal seams of the dough and place the roast on a baking pan lined with foil--seam side down.
Roast the meat at 350-375 degrees for 2 1/2 hours (you may want to insert a thermometer to check for doneness).
Remove from the oven and crack the clay in several places using a hammer.
Peel off the foil and allow the roast to rest for 10 minutes before carving.