1. Preheat your oven to 375°F (190°C). Lay the sliced onions on a large baking tray, drizzle with 2 tablespoons of olive oil, sprinkle with salt and pepper, and toss to coat evenly. Spread them out in a single layer and roast for 25-30 minutes, stirring halfway through, until the onions are golden and caramelised. This slow roasting brings out their natural sweetness, something my mum always swore by.
2. While the onions are roasting, season the chicken breasts with salt and pepper on both sides.
3. Heat the remaining tablespoon of olive oil in a large skillet over medium-high heat. Add the chicken breasts and cook for about 5-6 minutes on each side until golden brown and cooked through (internal temperature should reach 165°F/74°C). Remove the chicken from the pan and set aside, keeping it warm.
4. Lower the heat to medium and add the minced garlic to the same skillet. Sauté for about 1 minute until fragrant, being careful not to burn it.
5. Pour in the balsamic vinegar, stirring to deglaze the pan and loosen any browned bits. Let it simmer for 2-3 minutes until slightly reduced and syrupy.
6. Stir in the heavy cream and Dijon mustard, mixing well to combine. Let the sauce simmer gently for 3-4 minutes until it thickens slightly. Add the fresh thyme leaves and season with additional salt and pepper to taste.
7. Return the roasted onions and chicken breasts to the skillet, spooning the sauce over the top. Let everything warm together for a minute or two so the flavours meld.
8. Sprinkle with fresh parsley before serving to add a pop of colour and freshness.

I remember the first time I used this method, watching the onions transform in the oven while the balsamic sauce bubbled gently on the stove. It’s a simple rhythm that feels almost meditative — the kind of cooking that invites you to slow down and breathe in the moment.