Preheat oven to 400°F. Put 2 garlic cloves and a sprig of rosemary in the cavity of each hen. Season with pepper. Fold legs back and tie together. Take foil squares and make shallow dish large enough to fit a hen, with an inch to spare all the way around. Place foil dished on heavy duty baking sheets. Layer ½ inch kosher salt in the bottom of each dish. Center a hen in each dish. In a large bowl mix kosher salt and water to create a paste. Coat each hen to a thickness of ½  inch with salt paste, leaving no part of the hen exposed. Bake 40 to 50 minutes depending on  size.

To serve: Use a knife to cut salt around the base of each hen. Use a heavy spatula (or two) to carefully remove the hens from foil dishes to a platter. Decorate platter with sprigs of rosemary. At the table, use a wooden mallet to crack the salt casing, then use a pastry brush to dust the salt away from the hens and serve. I always do this dish on a candle lit glass top table and intentionally make a pretty big mess. My favorite wine with this is a Gewürztraminer.