Sauté the aromatics: Heat the olive oil in a large frying pan over a medium heat. Add the diced onion and cook for 5-7 minutes, stirring occasionally, until the pieces are translucent and softened, and you can smell a sweet, earthy aroma. Add the minced garlic and cook for another 30 seconds until fragrant, being careful not to let it brown too much — the smell should be mellow, not sharp.

Build the sauce base: Pour the tomato passata, chicken stock, apple cider vinegar, and Worcestershire sauce into the slow cooker. Stir in the brown sugar, smoked paprika, cumin, mustard powder, salt, and pepper. Whisk everything together until the sugar dissolves and the sauce looks a deep, glossy brick-red.

Add the sautéed onions: Scrape the softened onion and garlic mixture into the slow cooker and stir to combine. The colour of the sauce will darken slightly, and you'll see tiny flecks of caramelised onion throughout.

Nestle in the chicken: Place the chicken breasts into the sauce, ensuring they are mostly submerged. If they aren't, spoon some sauce over the tops. The raw chicken will look pale and slightly firm against the rich, red sauce.

Cook low and slow: Cover the slow cooker with the lid and cook on LOW for 6 hours (or HIGH for 3 hours). After about 4 hours on low, you'll notice the chicken has turned a deep brownish-red and the sauce is bubbling gently around the edges. The kitchen will smell wonderfully smoky-sweet.

Shred the chicken: Once the cooking time is up, use two forks to gently pull the chicken apart. It should shred with almost no resistance, the fibres separating easily. The meat will be a rich, dark mahogany colour, and the sauce will have thickened slightly. If the chicken feels tough, it needs another 30-45 minutes.

Finish and rest: Let the shredded chicken sit in the sauce for 10-15 minutes before serving. This resting time allows the meat to reabsorb some of the cooking liquid, resulting in a juicier, more cohesive final dish. The sauce will look thicker and cling beautifully to the shreds.