Gone are the days when meat-free burgers had more than a passing resemblance to cardboard. Now, innovative chefs across the country are whipping up plant-based patties that are more than just a substitute for traditional hamburgers – in some cases, they're even tastier. From patties packed with vegetables and beans and doused in house-made sauces, to meat substitutes that rival the real thing, we reveal the best plant-based burgers in America.