Birria Tacos Recipe is very good Birria tacos, if you haven’t heard of them yet all over social media and the internet, is traditionally an addictive sweet, sour, slightly spicy, and utterly savory Mexican beef stew that’s slow cooked until the beef is tender and fall-apart juicy and delicious. Someone had the bright idea to stuff this beefy goodness into a taco shell, and then dip the whole mess into the stew and fry it up. They blew up after that, and the rest is history. But unlike most fad foods, Birria tacos are so good you’ll be making them every week.