Heat a small cast iron saucepan (with lid) on a medium heat. Dry roast the ancho chilli, turning, until fragrant. Place chilli on a chopping board, slice finely (whole or half to your liking) and set aside. In the same saucepan over a medium high heat add 1 tbsp of olive oil and seal the beef on all sides, in batches, remove and set aside.
In the same saucepan over a medium heat, add remaining olive oil. Fry shallots and garlic until soft. Add tomato paste, stir, add ancho, chipotle, cumin, oregano, beef stock, vinegar and stir. Cook on a low heat for 20 minutes, stirring occasionally. Add chocolate and stir until melted, then add the beef and stir to coat and warm the beef through. Turn off heat, cover and set aside.
Heat tortillas on a hot dry frying pan until soft, about 10 – 15 seconds each side. Place each warmed tortilla in a clean tea towel, cover, and repeat until all tortillas are warm.
To assemble, fill each tortilla with cubes of beef. Garnish with a slice of avocado, crumbled feta, coriander and serve with lime on the side.
+ Serves 2 + Preparation: 10 min. Cooking Time: 20 min.