You could use the frosting that they use at the bakery. It is at the end of the recipe. It's very yummy (and very sweet).

For my cheesecake frosting I just beat philly cheese and lemon zest and then add a dribble of milk and then icing sugar until it seems right. It's the lemon zest that gives it the special taste.
For more lemony flavour you could use a couple of teaspoons of lemon juice instead of milk.