Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large mixing bowl, cream together the unsalted butter, powdered sugar, and granulated sugar until light and fluffy, about 2-3 minutes.

Add in the orange zest and vanilla extract, mixing on low speed until evenly distributed.

Gradually sift in the all-purpose flour and sprinkle in the salt, mixing until just combined.

Turn the dough onto a floured surface, and shape it into small balls or roll it out to cut into desired shapes.

Place the shaped cookies onto the prepared baking sheet, spaced evenly apart.

Bake for 12-15 minutes, until lightly golden on the edges but still soft in the center.

Let cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.

Dust the cookies lightly with powdered sugar before serving if desired.