In a zipper baggie, mix together the milk and vinegar. Put the chicken pieces into the baggie and place it into the refrigerator. Let chill for 5 minutes or up to 2 hours if you have the time.Leave the chicken in the bag and pour the buttermilk into a shallow bowl. Whisk in the egg.
In a deep fryer, add oil until it is about 3 inches deep. Add in the bacon grease if you have some (you can see mine at the bottom of the fryer). Turn the heat dial to 375 F and let it preheat until it reaches the desired temperature.
Place all the coated pieces in a gallon-size zip baggie along with the leftover flour, and shake until evenly coated. Let sit inside the bag while the oil finishes heating up.
Use a meat thermometer in the thickest part of the chicken to check for an internal temperature of 165 degrees F.Drain the chicken on a paper towel-lined dish or on a wire rack over a paper towel-lined dish. Serve and enjoy!