Prep and preheat. Heat the oven to 400°F (200°C).
Pat the chicken breasts dry and season both sides with salt and pepper. This helps them sear well and stay juicy.
Crisp the bacon. In a large oven-safe skillet over medium heat, cook the bacon until starting to crisp, 5–7 minutes. Transfer bacon to a plate and pour off most of the fat, leaving about 1 tablespoon in the pan.
Sear the chicken. In the same skillet over medium-high heat, add the olive oil.
Sear chicken 2–3 minutes per side until lightly golden. You’re not cooking it through yet—just building flavor. Remove chicken to a plate.
Soften the aromatics. Reduce heat to medium.
Add onion and a pinch of salt. Cook 3–4 minutes until softened and lightly golden. Stir in garlic and cook 30 seconds until fragrant.
Make the sauce. Stir in passata, barbecue sauce, chicken stock, apple cider vinegar, Worcestershire, Dijon, smoked paprika, and thyme.
Simmer 3–5 minutes, stirring, until slightly thickened. Taste and adjust salt, pepper, or vinegar for balance. The sauce should be tangy, a little smoky, and not overly sweet.
Assemble. Nestle the chicken breasts back into the sauce.
Spoon sauce over the top. Lay bacon pieces across each breast, then sprinkle with shredded cheese.
Bake. Transfer the skillet to the oven. Bake 12–18 minutes, depending on thickness, until the chicken reaches an internal temperature of 165°F (74°C) and the cheese is melted and bubbly.
Rest and serve. Let it rest 5 minutes.
Spoon extra sauce over the chicken, garnish with parsley, and serve hot.