Place the white chocolate in a batter bowl and microwave on high for 30 seconds. Stir. Microwave another 30 seconds, stir, and repeat until the chocolate has melted. Do not overheat, but do make sure all of the particles are melted Set aside.
On a plate, microwave the cream cheese on half-power for 1 minute to soften. Set aside.
On another plate, microwave the butter on half power for 30-40 seconds, to soften it.
In electric mixer, whip the softened cream cheese for 2 minutes. Make sure it is completely fluffed, with no particles of cream cheese remaining.
Slowly beat in the melted chocolate and then gradually beat in the butter in chunks, and then the juice. Beat until light and fluffy.
Spread on cake, and also makes a great piping mixture for roses, borders, and etc.
Note: "This recipe was posted in response to a request for the Buttercream Frosting recipe from Publix Grocery Store chain in Florida. I must say this is the best Buttercream I have every tasted! Just remember, you absolutely must use real White Chocolate! You cannot use vanilla chips or almond bark; the results will be very disappointing if you do. The brand called for "White Satin" is not available in my area but any name brand white chocolate baking bar will work." - Glenda's Kitchen.