Cracking the salt open makes a dramatic presentation—you might even want to serve it at the table!

Combine oil, onion, garlic, horseradish, and pepper in a heavy plastic bag; mix well. Add roast; coat well with marinade. Marinate in refrigerator 2 Hours or overnight.
Preheat oven to 350 degrees F. Line a 9”x13” roasting pan with aluminum foil.
Combine kosher salt and water to form a thick paste. Pat 1 cup of the salt paste into a 1/2-inch thick rectangle in the center of the pan.
Pat roast dry with paper towels. Place roast on salt layer; gently pack remaining salt paste all around meat to seal well. Bake for 2 Hours. The crust may crack slightly. Remove from oven; let stand 10 Minutes. Crack salt crust open, remove and discard.
Slice and serve immediately.

What about freezing once baked?
I would remove the baked roast from the salt crust and slice. wrap well & freeze
can this be done on a brisket? can it bake longer, low and slow?
Hi. We haven’t tried it. Not sure how the salt crust will react to the longer cook time. If you do, let us know how it worked.