Split the chicken breasts and remove the meat from the bones. Remove skin, if desired. Brush the chicken with some of the melted butter, margarine, or oil. Place chicken, skin side down, on the unheated rack of a broiler pan.
Place chicken under the broiler 4 to 5 inches from the heat. Broil for about 6 minutes or until the chicken is lightly browned. Turn skin side up; brush with more melted butter, margarine, or oil. Broil for 6 to 9 minutes more or until chicken is no longer pink.
Meanwhile, for a vinaigrette dressing, in a large skillet, cook the chopped bacon and chopped red onion until the onion is tender but not brown and the bacon is cooked but not crisp. Drain off the fat. Add the brown sugar and molasses. Cook and stir until the mixture begins to simmer.
Stir together the water, the red wine vinegar, Dijon-style or stone-ground mustard, and cornstarch. Add to the mixture in the saucepan. Cook and stir until the mixture is slightly thickened and bubbly. Cook and stir for 2 minutes more. Remove the saucepan from the heat.
To serve, on each of 4 serving plates, mound 1/4 of the torn spinach leaves. Bias-slice a chicken breast and arrange on top of the spinach. Garnish with cherry tomato halves. Drizzle each serving with some of the vinaigrette. Cover and refrigerate the remaining vinaigrette dressing for another use. Reheat the vinaigrette before using. Makes 4 servings.
You'll find free-range chicken in some large supermarkets.