Best Baked Potato Ever?

 Baked Potatoes with garlic/rosemary butter topping

My wife brought this recipe back from a trip to Chicago.  The recipe claimed they were the best baked potatoes ever.  We thought the potatoes were excellent and the topping was great.  However, we were juggling the oven times with the bread, pork chops and potatoes leaving us unable to make a definitive judgement. 

Place 2 1/2 cups of rock salt in a 13x9 baking pan along with 2 cloves of garlic with the heads chopped off, 2 sprigs of rosemary and 5 scrubbed baked potatoes.  Cover and bake for 75 minutes at 450 degrees.  Remove from oven, toss the rosemary, remove the garlic and turn your oven up to 500 degrees.  While the oven is reheating, add 4T room temperature butter to a bowl, 1 T finely chopped rosemary and squeeze in the cooked garlic using a towel, with a fork mash the garlic into the rosemary and butter.  Brush the potatoes with olive oil and bake uncovered for 15 minutes to crisp the skins.  Brush the salt off the potatoes, slit the tops and spoon in the butter herb mixture.  The main comment at dinner was more topping, so the next time we make these potatoes think we'll use a cube of butter and 3 garlic cloves. 

The potatoes, garlic and rosemary lying on a bed of salt prior to baking