4 large slices of roasted red bell pepper, from a jar
1 shallot, diced
4 boneless, skinless chicken breasts, about 4 to 6 ounces each
1 1/2 tablespoons olive oil
1/4 cup white balsamic vinegar
3/4 cup chicken stock
Cut a deep horizontal pocket in the side of each chicken breast. Make the pocket as large as you can without piercing the top or bottom of the breast. Place 1 slice of red pepper and 1 teaspoon of diced shallot in the pocket of each chicken breast. Secure the pocket with toothpicks threading along the side to close.
Heat the oil in a heavy oven-proof skillet until it begins to smoke. Cook each side of the chicken until golden brown.
Add the vinegar and chicken stock and bring to a boil. Lower the heat and gently simmer the chicken for 2 or 3 minutes per side until cooked through.
Remove the chicken breasts from the skillet and keep warm. Continue to cook the sauce until it is reduced to a thick syrup.
Taste the sauce and season with salt and pepper. Spoon the sauce over each chicken breast to serve.