"This is a great recipe from my Grandma. We love these tacos! They are not the most-Mexican tacos around, but they are a family favorite for sure. These take some getting used to for some people, but you will grow to love and crave them. They are great with ketchup. I know it's blasphemy to put ketchup on tacos, but trust me!"
Heat a large skillet over medium-high heat. Cook and stir beef in the hot skillet until some of the fat renders, 1 to 2 minutes; add potatoes, vinegar, garlic, and thyme. Continue to cook the beef mixture, stirring frequently, until the beef is completely browned and crumbly and the potato is soft, 12 to 15 minutes more.