Prep your tools: Line two baking sheets with parchment. Have a zester ready and let the butter sit out until soft but not greasy.

Zest the orange: Use a microplane to remove the bright orange layer only. Avoid the white pith, which is bitter. You’ll need about 2 packed teaspoons of zest.

Cream the butter and sugars: In a mixing bowl, beat softened butter with granulated sugar and a couple tablespoons of powdered sugar until light and creamy, about 2 minutes. Don’t whip it too fluffy; you want a smooth, spreadable paste.

Add flavor: Mix in orange zest, 1 teaspoon vanilla, and 1–2 teaspoons orange juice or a few drops of orange extract. The dough should smell citrusy but not wet.

Add dry ingredients: Sift in flour and a pinch of kosher salt. Beat on low until the dough just comes together and no dry patches remain. It should feel soft and slightly crumbly, but hold when pressed.

Shape the dough: Turn the dough onto a sheet of parchment. Form it into a log about 2 inches in diameter, or flatten into a 3/4-inch thick disk for cut-outs. For slice-and-bake, roll the log in turbinado sugar for a sparkly edge.

Chill: Wrap well and chill for at least 1 hour, or up to 48 hours. Chilled dough slices cleanly and bakes without spreading.

Preheat and slice: Heat the oven to 325°F (160°C). For logs, slice into 1/4-inch rounds and place on prepared sheets. For cut-outs, roll the disk to just under 1/4 inch and cut with a 2-inch cutter, gathering and re-rolling scraps as needed.

Bake: Bake 12–16 minutes, rotating once. Look for matte tops and lightly golden edges. Don’t wait for full browning; shortbread should stay fairly pale.

Cool and finish: Let cookies rest on the sheet for 5 minutes, then move to a rack. When cool, dip one side in melted dark chocolate or drizzle over the top for a lovely contrast.