Preheat your oven to 350°F (175°C). This is the crucial first step to ensure your cookies bake perfectly and achieve that lovely golden edge.

Cream the softened butter, granulated sugar, and powdered sugar together in a mixing bowl until the mixture is light and fluffy, about 3-5 minutes.

Add the egg, orange zest, and vanilla extract to the buttery mix. Blend until everything is well combined.

Whisk together the all-purpose flour, baking soda, cream of tartar, and salt in a separate bowl.

Gradually mix the dry ingredients into the wet ingredients, stirring until just incorporated.

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

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

Cool the cookies on the baking sheet for a few minutes before transferring them to a wire rack.

If desired, frost them with orange frosting once they've cooled completely.