Heat a large skillet over medium-high heat. Add the ground beef and onion and cook until the beef is cooked through and no longer pink. Drain off the grease and return the beef to the skillet.

Add the taco seasoning and Jalapeño pepper to the skillet and sauté for a couple of minutes until the seasoning is fragrant. Stir in the pinto beans and sprinkle in the flour. Cook, stirring to distribute the flour well, for a minute or two. Add the diced tomatoes and beef stock (or water). Lower the heat and simmer for 15 minutes.

Lay the tortillas out on the counter. Sprinkle some of the cheese on half of each tortilla. Divide the beef mixture between the tortillas and top with the remaining cheese. Fold the tortilla in the half.

Wipe out the skillet and return it to the stovetop. Heat over medium heat and add a glug of vegetable oil. Place the folded tortillas in the pan and fry for a couple of minutes on each side until browned and crispy. Transfer the tacos on a plate lined with paper towel for a few minutes before serving.

Serve the tacos warm and top with salsa, sour cream or avocado fresca as desired.