In a large bowl, have your child stir together the maple syrup, ketchup, cider vinegar, Worcestershire sauce, dry mustard and salt. Add the chicken breasts, stirring to coat with the sauce, cover and let marinate for at least one hour (or as long as overnight). Just remember, if your young helper wants to taste the sauce, have her do it before you add the chicken.
Preheat the oven to 375°F (190°C). Arrange the chicken breasts on a lightly greased, foil-covered (saves on cleanup) baking sheet, spreading them out so that they're not crowded. Spoon (or brush - a good kid job )a little of the marinade over each chicken breast, then place the pan into the oven and bake for 30 to 40 minutes, until cooked through.
In the meantime, if you want to use the leftover marinade as a dipping sauce, pour it into a small saucepan and bring to a boil over medium heat. Lower the heat and let simmer for 5 or 6 minutes, until slightly thickened.
Serve the chicken breasts plain, or with a little of the maple sauce spooned over top. Or cut them into strips and serve the sauce separately in a small bowl for dipping.
Sorry, there is no nutrition information available for this recipe.