Cream butter and sugar, using electric mixer, until light and fluffy, about 5 to 7 minutes.
Add eggs, one at a time and mix well after each addition.
Alternate adding flour and buttermilk to creamed mixture, mixing only until well incorporated. Don’t over mix. Scrape down sides of bowl a few times during mixing.
Stir in vanilla.
Divide batter into three (9 inch) greased and floured cake pans and spread evenly. Pick up pans slightly and drop on counter 2 or 3 times to remove air bubbles and help level out cake batter.
Bake in a 350 degree preheated oven for 25 to 30 minutes or until a toothpick inserted comes out clean. Let cakes cool in pans 10 minutes. Place on cooling racks to continue cooling.
Mix together well. Make in advance of the cake so the sugar has time form a syrup.
When cake has cooled, place one layer on a cake plate and poke the top a few times with a fork. Spread a third of the filling over the top. Repeat with remaining layers and filling. Store in refrigerator three days.
Before serving, I like to sprinkle some sweetened flaked coconut on the top.