Lemon Truffle Cake Recipe | Recipe Girl Cake 2 1/4 c flour 1 2/3 c sugar 3 1/2 t baking powder 1 t salt 1 1/4 c milk 3/4 c butter 1 t vanilla 5 lg egg whites LEMON TRUFFLE FILLING: 3/4 c sugar 3 T cornstarch 1/4 t salt 1 c water 2 lg egg yolks 1 T butter 1/3 c lemon juice, freshly squeezed 1 t grated lemon zest 6 oz (1 c) chopped white chocolate or chips 1 (8 oz) package cream cheese WHIPPED CREAM FROSTING: 1 c whipping cream 3 T powdered sugar