Preheat Oven: Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.
Cream Butter and Sugar: In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.
Add Egg and Flavorings: Beat in the egg, orange zest, orange juice, and vanilla extract until well combined.
Mix Dry Ingredients: In another bowl, whisk together the flour, baking powder, and salt.
Combine Mixtures: Gradually add the dry ingredients to the wet mixture, mixing until just combined. Chill the dough in the refrigerator for about 30 minutes to make it easier to handle.
Shape and Bake: After chilling, scoop tablespoon-sized portions of dough and roll them into balls. Place them on the prepared baking sheet, spacing them about 2 inches apart. Bake for 10-12 minutes, or until the edges are lightly golden. Allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.
Prepare the Creamsicle Frosting:
Make the Frosting: In a mixing bowl, beat the softened butter until creamy. Gradually add the powdered sugar, mixing well. Stir in the orange juice and vanilla extract until smooth and fluffy.
Frost the Cookies: Once the cookies are completely cooled, frost them with the creamsicle frosting.
Garnish: Optionally, sprinkle a little orange zest on top of the frosted cookies for added flavor and decoration.