Sauté the Aromatics: Heat the olive oil in a large, deep frying pan or skillet over a medium heat. Add the diced onion and cook for 5-7 minutes, until soft and translucent. Add the minced garlic, ground cumin, smoked paprika, and oregano. Stir continuously for about 1 minute until the spices are wonderfully fragrant. This step is key to building the flavour base.

Create the Sauce: Stir in the chopped chipotle peppers, adobo sauce, and tomato purée. Cook for another minute, then pour in the tomato passata and chicken stock. Bring the mixture to a gentle simmer, stirring occasionally.

Cook the Chicken: Season the chicken breasts with a little salt and pepper. Carefully place them into the simmering sauce, ensuring they are mostly submerged. Reduce the heat to low, cover the pan with a lid, and let it simmer gently for 15-20 minutes, or until the chicken is cooked through and tender. The exact time will depend on the thickness of your chicken breasts.

Shred the Chicken: Once cooked, remove the chicken from the pan and place it on a cutting board. Using two forks, shred the meat. I find that pulling the forks in opposite directions works best to get fine, even shreds.

Finish the Filling: Return the shredded chicken to the sauce in the pan. Stir everything together and let it simmer uncovered for another 5 minutes. This allows the chicken to soak up even more of the sauce, and for the sauce to thicken slightly.

Add the Finishing Touches: Turn off the heat and stir in the fresh lime juice. This brightens all the smoky, deep flavours. Have a taste and add any extra salt or pepper if needed.

Warm the Tortillas: While the chicken rests, warm your tortillas. You can do this by heating them one by one in a dry frying pan for about 30 seconds per side, or by wrapping a stack of them in foil and placing them in a warm oven (150°C/130°C fan) for 10 minutes. A warm, pliable tortilla makes all the difference. You can learn more about the authentic origins of this method from the long history of the taco.

Assemble and Serve: It's time to build your tacos! Spoon a generous amount of the shredded chicken mixture into each warm tortilla. Top with sliced avocado, cherry tomatoes, fresh coriander, and a little soured cream. Serve immediately with extra lime wedges on the side.