Preheat oven to 350 degrees F (175 degrees C). Butter and flour two 9 inch round cake pans.
In a double boiler melt the white chocolate over hot water. Set aside to cool slightly.
In a medium bowl whisk the flour, baking powder, and salt.
In a large bowl cream the butter or margarine and white sugar until light and fluffy. Beat in the melted white chocolate and the vanilla.
In three additions alternately beat in the flour mixture and the milk into the creamed mixture. Beat only until just smooth. Pour batter into prepared pans.
Bake at 350 degrees F (175 degrees C) for 25 to 30 minutes, or until the top is golden.
