1) Beat together the sugar, butter, salt, vanilla, and eggnog flavor.
2) Add the flour, nuts, and fruit, and stir until just combined.
3) Divide the dough in half, and shape each half into a log: square, triangle, and/or circle.
4) Wrap the logs in plastic, then aluminum foil; freeze for 1 hour.
5) Preheat the oven to 300°F. Lightly grease two baking sheets, or line them with parchment.
6) Remove the dough from the freezer one log at a time, unwrap, and place on a clean work surface.
7) Cut the log into 1/4"-thick slices, and transfer the cookies to the prepared baking sheets.
8) Bake the cookies for 25 to 35 minutes, or until they feel firm. They won't brown much; the long, slow baking process is meant to prevent them from darkening.
9) Remove the cookies from the oven, and transfer them to a rack to cool. When completely cool, wrap airtight and store at room temperature; freeze for longer storage.
Yield: 3 dozen to 5 dozen cookies, depending on diameter.