Preheat oven to 350 degrees.

In large bowl, cream butter and sugar for 4 minutes until light and fluffy. Add eggs, vanilla, grapefruit juice, and grapefruit zest and stir to combine.

Stir in flour, baking powder, baking soda, and salt and mix just until combined.

Drop dough onto light colored baking sheet.

Bake for 9-11 minutes. Let cool.

In a large bowl, beat the butter until creamy. To melt white chocolate, use a double To melt white chocolate:

When working with white chocolate, the key is to slowly melt it. You can use a double boiler or microwave method. If using the microwave, use only 40-50% power and cook at 30 second increments. After cooking it for 30 seconds, move to 15 second increments at only 50% power. White chocolate can burn easily! It usually takes less than a minute to melt white chocolate, depending how much you are melting at one time. Stir the white chocolate after each time to test if it is melted enough. Let cool slightly.

Beat in the melted white chocolate. Add powdered sugar and beat at low speed, scraping the sides and bottom of the bowl, until light and fluffy.

Frost each cooled grapefruit cookie with white chocolate buttercream. Sprinkle with grapefruit zest.

**These cookies are excellent frozen and eaten right out of the freezer.