Combine oil, onion, garlic salt, basil, marjoram, thyme and pepper in a heavy plastic bag. Mix well. Add roast; coat well with marinade. Marinate in refrigerator 2 hours or overnight. Line roasting pan with foil. Combine kosher salt and water to form a thick slush. Pat 1 cup of mixture into a 1/2-inch thick rectangle in pan. Pat roast dry with paper towels. Insert meat thermometer. Place roast on salt layer. Pack remaining salt mixture around roast to seal well. Place roast in 425F oven and roast 16-18 minutes per pound for rare (140 degrees), 20-22 minutes per pound for medium (160 degrees) or 25-30 minutes for well done (170 degrees). Remove roast when thermometer registers 5 degrees below desired doneness. Let roast stand 5-10 minutes in salt crust. To remove crust you may need to use a hammer. After removing crust, whisk away any remaining salt crystals with a pastry brush.

pounds. Smaller roasts will cook before the crust hardens. For larger roasts, cooking time will not be much longer than for smaller roasts. Use a meat thermometer. Use only coarse kosher salt, not table salt or rock salt.

More tips from the Abj:

Buy an extra box of salt if cooking a roast larger than 6 pounds.

Insert meat thermometer before putting the meat in the oven. When the crust hardens, the thermometer may be difficult to insert. Wiggle the thermometer so the salt iisn't packed against the stem, which could produce a false temperature reading.

Don't pack the roast in salt ahead of time, or the salt will fall off. Don't moisten the salt with more water than the recipe calls for, or the salt will fall off.

Sprinkle a thin layer of salt slush over the roast first, then add a thicker layer. The salt will cling to the meat better. But if the salt still falls off in a few places, don't worry.