Tomato paste is a flavorful gluten-free thickener with the bonus of adding great color to braises and stews. I prefer the products that come in a squeezable tube, because they stay fresh for months.
Using poultry shears, cut the chicken breasts in half crosswise. Pat dry and sprinkle on both sides with salt and pepper. In a large nonstick frying pan over medium-high heat, warm the oil. Add the chicken and cook until brown, about 3 minutes per side. Transfer to a plate.
Pour off the fat from the pan and return the pan to medium-high heat. Add the pancetta a