1) Preheat oven to 350 degrees. Grease and flour or line with parchment two 9inch pans (or three 6 round).
2) Cream the butter and sugar with an electric mixer on medium until fluffy. Add vanilla, then add eggs one at a time, beating on low just until they are mixed in.
3) In a separate bowl, sift together the flour, baking soda, baking powder and salt. Starting with the flour mixture, add the flour and the buttermilk (alternating one then the other) into the sugar/egg mixture on low speed. When everything is mixed in, scrape down the bowl by hand.
4) Pour batter into the pans and bake for 25-30 minutes, until a toothpick inserted in the middle comes out clean. Cool the cake before frosting.
1) In a small saucepan, mix together all ingredients except the vanilla and the extra 2 Tablespoons of butter. Heat over medium and bring to a boil. Stirring frequently to prevent burning, let the mixture boil for a good one minute. (I actually use a candy thermometer and let it reach 238 degrees, but if you don’t have one, just make sure you boil it for a good solid minute).
2) Take off the fire and add in the vanilla and the 2 Tablespoons butter. Cool the mixture, occasionally giving it a vigorous stir, until it is still warm (but not HOT) and has thickened enough to spread. Spread it over the cake, moving fairly quickly because it will set as it cools. It will be a thin coating, not a thick layer. Let it set completely before cutting into the cake.