Start by trimming the chicken breasts and slicing them into thinner pieces. Lay them flat and gently pound with a meat mallet until about ¼-inch thick. This step makes sure the chicken cooks evenly and stays juicy. Season both sides with salt and pepper to lock in flavor right from the start.
Heat olive oil in a large skillet over medium heat. Add the pancetta and let it sizzle until golden and crisp. Scoop it out onto a paper towel-lined plate, leaving the rendered fat behind. That fat is going to be the secret flavor base for the sauce.
In the same skillet, sear the chicken on both sides until golden brown, about 4–5 minutes per side. Work in batches if needed so the pan isn’t overcrowded. Once cooked, transfer the chicken to a plate and keep the flavorful drippings in the skillet.
Lower the heat to medium and add the diced shallot. Cook until it softens and turns translucent. Then stir in the garlic and let it cook for about 1 minute, releasing that amazing aroma without burning it.
Pour in the white wine or vermouth, scraping up all the browned bits from the pan. Add the chicken broth and heavy cream, stirring until it simmers and thickens. This is where the sauce becomes beautifully rich and velvety.
Stir in the thyme leaves and return the pancetta to the skillet. Place the chicken back in and spoon the sauce over each piece. Let it cook together for another 5–7 minutes so the flavors meld. Finish with butter for that glossy, luxurious touch.