Using the tip of a sharp paring knife, make 20 evenly spaced small slits about 1 1/2-inches deep all over the pot roast. Using your fingers, insert the garlic cloves as deep into the meat as possible. Season the roast on all sides with the salt and pepper.
Preheat the oven to 300 degrees F.
Heat a Dutch oven just large enough to hold the roast over high heat. Add the oil and, when hot, sear the meat until very well browned on all sides, about 4 to 6 minutes per side. Don't be afraid to let the roast get very brownthis is where a lot of the flavor comes from. When the roast is evenly browned on all sides, carefully add the broth and cover the pot. Transfer the roast to the oven and cook, turning once or twice during the cooking time, until it is falling apart-tender, 3 to 3 1/2 hours. Check occasionally to make sure that there is always at least 1-inch of liquid on the bottom of the pan. Add more water, as necessary, to keep this level during the entire cooking process.
When the roast is very tender, remove it from the oven and let rest briefly. Increase the oven temperature to 375 degrees F. Using 2 forks, pull the meat apart into thin shreds, mixing the meat with the accumulated drippings left in the bottom of the pan. Allow meat to cool slightly before making po''boy.
Cut the po'boy bread into the desired lengths according to guests' preferences, (most po''boy come in 4, 6, or 8-inch sizes.) Slice the bread(s) in half lengthwise and spread both cut sides liberally with mayonnaise, to taste. Spoon the moist meat filling over the bottom portion of each piece of bread, drizzling with extra drippings, then top with grated provolone and place in the oven just until cheese is melted, 2 to 3 minutes. Remove from the oven and top with lettuce, tomatoes, and pickles. Sprinkle with hot sauce, if desired, top the po'boy with the other half of bread, and serve immediately.
* Traditional New Orleans po'boy loaves are airy, long French breads. If you cannot find po'boy bread in your area, substitute any long Italian or French bread loaves that are not too dense. If the only bread you can find is very dense, consider pinching out the center doughy portions so that your po'boy is not overly bready.