Preheat the oven to 350°F (175°C).

In a mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.

Beat in the egg, vanilla extract, lemon zest, and orange zest until well combined.

In another bowl, whisk together the flour and baking powder.

Gradually add the dry ingredients to the wet mixture, mixing until just combined.

Drop spoonfuls of dough onto a baking sheet lined with parchment paper.

Bake for 10-12 minutes or until the edges are lightly golden.

Remove from the oven and let cool completely.

In a small bowl, whisk together the powdered sugar, lemon juice, and orange juice until smooth.

Drizzle the glaze over the cooled cookies.

Allow the glaze to set before serving.