In a food processor, combine granulated sugar and fresh orange zest. Pulse until finely blended and moist, about 1-2 minutes.

Add all-purpose flour, softened unsalted butter, salt, and optional orange extract to the orange sugar mixture. Pulse until dough holds together, about 30-45 seconds.

Divide the dough into two equal portions and shape into logs. Wrap tightly in plastic wrap and chill in the refrigerator for at least 2 hours.

Preheat oven to 350°F (175°C) and line two baking sheets with parchment paper. Remove chilled dough logs for easier slicing.

Slice each log into 1/2-inch thick slices and place evenly on baking sheets. Bake for 10-12 minutes until the edges are golden brown.

Let cookies cool on baking sheets for 5 minutes before transferring to a wire rack. Melt the chopped chocolate and dip half of each cookie into it.