Preheat oven to 350 degrees
Over low heat melt 4 Tbl. butter with garlic in a heavy sauce pan.
Increase temperature to medium high, add 1/2 cup brown sugar stirring continuously until the butter and sugar are combined.
Remove from heat and continue stirring until mixture is smooth. Will be thick and grainy.
Place chicken breasts in a 4 Qt. baking dish coated with cooking spray.
Spoon brown sugar mixture over chicken and bake uncovered for 30 minutes.
Remove from oven and reduce heat to 300 degrees.