Preheat the oven to 325 degrees. Grease and flour a 9 inch loaf pan.
With an electric mixer, cream the butter, sugar, and vanilla until fluffy. Add the eggs, 1 at a time, beating until fluffy. Add the cream cheese and blend until well combined.
In another bowl, sift the flour, baking powder, and salt together. Place the currants in a small bowl. Add 1/4 cup of flour mixture to currants and stir currants until coated.
Add remaining flour mixture to the batter, and mix, alternating with the buttermilk. Blend until smooth. Add the currants and stir until well combined.
Pour the batter into a prepared pan. Bake until tester comes out clean, about 1 hour and 25 minutes.
Remove to a rack and let the cake rest in the pan for 10 minutes. Carefully remove cake from pan to cooling rack.
In a small bowl, combine the confectioners' sugar with lemon juice, and spread on the warm cake. Let cake cool completely before serving.