Preheat oven to 350 degrees F.
In a medium bowl combine all the ingredients and beat on low for 30 seconds, then on medium speed for 2 minutes.
Pour evenly into two greased 8-inch cake pan. Bake for 40-45 minutes, or until toothpick comes out clean. Let cool and remove from pan.
For the buttercream, beat the butter until light and fluffy then add the icing sugar.
Add the wine, vanilla and orange zest. For a stiffer buttercream use less white wine, for a softer buttercream add a little extra white wine.
Stack the two cake layers with buttercream in between.
Frost and decorate as desired.