Winning frosting recipe. Hope it works. ETA: add 1/3 package of cream cheese and it's perfect. Please not this will be pretty liquidy.
Also on these boards
lemon cupcake with blackberry and raspberry buttercream. I had to bake the cake longer than the recipe called for. And I didn't put all the powdered sugar into the frosting, I just kept adding and tasting. It was a little less than 1/2 cup for each