Preheat oven to 350 degrees. Coat an 8x8 glass pan with cooking spray. Lay chicken breasts in pan, salt and pepper to taste, and add a small pat of butter to the top of each breast. Place in oven and bake for 20 minutes.
While chicken is baking add remaining ingredients together and mix with fork until well blended.
After the first 20 minutes is up, turn chicken breasts over. Spoon 1/2 of the honey mustard mixture evenly over each breast. Continue to bake for another 20 minutes.
After the second 20 minutes is up, turn breasts back over and top with the remaining half of the honey mustard. Bake 20 more minutes.
NOTE...if during the baking time the pan drippings start to "burn"...I add a little HOT water to the bottom of the pan to keep the chicken breasts moist.