Prep the chicken. Pat the chicken dry and season both sides with salt, pepper, and Italian seasoning. Pounding to an even thickness helps it cook evenly and stay juicy.

Get the skillet hot. Heat olive oil and 1 tablespoon butter in a large skillet over medium-high heat until the butter foams.

Sear the chicken. Add the chicken and cook 4–6 minutes per side, depending on thickness, until golden and almost cooked through. Transfer to a plate and tent loosely with foil.

Make the garlic butter base. Lower heat to medium. Add remaining 2 tablespoons butter to the skillet. Stir in the minced garlic and cook 30–45 seconds, just until fragrant. Don’t brown the garlic.

Bloom the tomatoes. Add the halved tomatoes and a pinch of salt. Cook 2–3 minutes, stirring, until they start to soften and release juices. If the pan looks dry, add a splash of white wine or broth to deglaze and scrape up browned bits.

Return the chicken. Nestle the chicken back into the skillet, spooning some of the garlicky tomato juices over the top.

Add mozzarella. Place mozzarella slices on the chicken. Cover the skillet and cook 1–2 minutes, just until the cheese melts. If you don’t have a lid, tent with foil.

Finish with basil and balsamic. Remove from heat. Add the torn basil, a squeeze of lemon, and drizzle with balsamic glaze. Sprinkle with red pepper flakes if you like a little heat.

Taste and adjust. Add a touch more salt or a bit more glaze to balance. Serve right away with the pan juices spooned over the top.