Preheat oven to 350 degrees F (180 degrees C).
Beat Egg (3) in a large mixing bowl. Add Granulated Sugar (1 1/2 cup), Distilled White Vinegar (1 tablespoon), and Pure Vanilla Extract (1 tablespoon) to beaten eggs. Mix well.
Slowly pour in Butter (1 stick), and add in Salt (1 pinch). Mix until combined, then stir in the Unsweetened Coconut Flakes (1 1/4 cup).
Pour the coconut mixture into 9-inch Pie Crust (1). Cook for 1 hour.
You can serve the pie warm, but it is best to wait for it to come to room temperature first.