Pick up the freshest ground beef you can find at your local butcher’s. Form i-inch thick patties that are the width of your freshly-baked biscuits or buns. Salt and pepper both sides. Heat a skillet so that it will sear your burger as soon as it touches the pan. Melt some bacon fat or heat some olive oil, and introduce the patties. Cook to your desired doneness (rosy in the center means extra juiciness and flavor!). Meanwhile, put the buns in the oven just enough to warm through and toast slightly on the top. Place your patty on the bottom bun and immediately place truffle slivers on the hot patty, with a thin sliver of cheese on top of that. Toss the onions in the pan you used for the patties, and sauté them until slightly brown. Place on top of the cheese, add the top bun, et voilà!