diet Coke Chicken

I got this recipe from my friend Dot years ago. She was born and raised in Mississippi and her "mama" made this for her. My mother met Dot on her trips to Hawaii, and Dot made this for her once. I think her mother probably used regular Coke, but Dot adjusted it to diet Coke because that's what she had on hand, and so that's how I make this too. This is good, ol' fashioned Southern white trash food at its finest... Diet Coke Chicken Spray a 8" square glass baking dish with Pam. Arrange boneless, skinless chicken breasts in pan (4 fit nicely, or use bigger dish for more). Squirt a blob of ketchup on each chicken breast, then top with a thin slice of onion. Pour about 1/2 can of diet Coke on top, about 1/2 inch in pan. Bake at about 350 for 30-40 minutes, basting with a spoon occasionally, until chicken is done and sauce is a little bubbly. Pour remainder of diet Coke over ice, splash with rum and garnish with lemon. Drink while waiting for chicken. Mmmm Mmmm Good.