• Preheat oven to 350 degrees F.
• Beat the butter and sugar until creamy. Beat in the egg and egg yolk.
• Mix together the flour, baking powder, salt, lime juice and lime zest. When well mixed, stir in the white chocolate chips.
• Roll dough into walnut sized balls and arrange on ungreased baking sheets spacing about 2 ½ inches apart.
• Bake at 350 degrees F for 10-12 minutes. Let cool on the baking sheet for 3 minutes, then transfer to a rack to finish cooling.

Lime Icing

• In a microwave-safe bowl or a 2-cup Pyrex measure, melt the butter.
• Add the lime zest and the powdered sugar to the melted butter, stirring well. It will be powdery and moist.
• Add the lime juice 1 tablespoon at a time, stirring until smooth enough to drizzle or spread. You can use all lime juice, but I recommend taste testing and if too lime-y for you, you can use less lime juice and a little milk. I like using all lime juice.