Preheat oven to 400 F.
To glass baking dish, add the chicken breasts and sprinkle minced onion, salt and pepper over top of the chicken.
In a small bowl, whisk together the honey, yellow mustard and vinegar. Pour over the top of the chicken.
Bake in the preheated oven for about 30-40 minutes, or until chicken is cooked through. Cooking time may vary depending on thickness of the chicken.
Serve Baked Honey Mustard Chicken.
To Freeze: Make the honey mustard marinade, add the chicken into plastic baggie or glass container and pour the marinade over the chicken. Freeze, thaw and bake as directed.