Prep the chicken: Pat chicken dry.
Season both sides with salt, pepper, and Italian seasoning. This helps build a flavorful crust and keeps the meat juicy.
Heat the pan: Warm a large skillet over medium-high. Add 1–2 tablespoons of olive oil and let it get hot until shimmering.
Sear the chicken: Place chicken in the pan and sear 4–5 minutes per side until golden.
You’re not cooking it through yet—just getting color. Remove to a plate.
Sauté the aromatics: Lower heat to medium. Add a splash more oil if needed.
Stir in the garlic (and sliced red onion if using) and cook 30–60 seconds until fragrant, not browned.
Deglaze with balsamic: Pour in the balsamic vinegar and scrape up the browned bits. If using honey or brown sugar, stir it in now. Let it bubble for 1–2 minutes to slightly thicken.
Add tomatoes: Toss in the cherry tomatoes and a pinch of red pepper flakes.
Cook 2–3 minutes, stirring occasionally, until some start to burst.
Return the chicken: Nestle the chicken back into the skillet, spooning some sauce and tomatoes over the top. Reduce heat to medium-low.
Finish cooking: Simmer gently 5–8 minutes, flipping once, until chicken reaches an internal temp of 165°F (74°C). If the sauce gets too thick, add a splash of water or stock.
Enrich the sauce: Swirl in the butter for extra gloss and richness.
Taste and adjust salt and pepper.
Add basil and serve: Turn off the heat and stir in the fresh basil. Serve immediately over rice, pasta, polenta, or with crusty bread to mop up the sauce.