Remove partially thawed pound cake from its container and slice the cake horizontally to create three layers.
With an electirc mixer, combine the butter, cream cheese, 2 tablespoons lemon juice, and confectioners' sugar in a large bowl until creamy and well blended.
Dip a pastry brush in the lemon juice and shake to sprinkle the cake layers with the remaining 2 T. lemon juice. Spread butter cream mixture on each layer and the top and sides of cake. Reform cake on serving platter.
Refrigerate at least 10 to 15 minutes before slicing and serving. Can be made ahead and refrigerated overnight.