Step 1Trim the silverskin from the tenderloin. Place the pork in a glass baking dish. Dissolve the salt and sugar in the water and pour it over the pork.
Step 2Refrigerate the tenderloin overnight for fullest flavor, or let sit at room temperature for at least 1 hour.
Step 1Heat the oven to 350 degrees. Toss the shallots with the olive oil. Scatter the shallots in a stainless steel, glass or ceramic baking dish (do not use aluminum, as this will discolor the shallots) that is large enough to accommodate the shallots in a thin layer. Roast until the shallots are a rich caramel color, about 40 minutes. Check during the end of the cooking time; do not let them burn.
Step 2Transfer to a saucepan and add the water. Simmer until the brown of the shallots colors the water, about 30 minutes. Taste the broth -- you may need to add a small amount of salt.
Step 1Grind the rosemary leaves, bay leaves and peppercorns in a spice grinder (or a coffee grinder dedicated to spices) until they become a fine powder. Remove the pork from the brine and pat it dry with a clean towel. Rub the spice powder over the entire surface of the meat.
Step 2Grill the pork over a medium fire until it reaches about 145 to 150 degrees (for medium) on a meat thermometer, about 20 to 25 minutes.
Step 3Slice the meat on the diagonal one-fourth inch thick. Serve with the roasted shallots and broth spooned over the top.