• Preheat oven to 350℉ Line a large baking sheet with a silicone baking mat or parchment paper.
• In a mixing bowl, combine butter, sugar, and eggs with a mixer for about until well blended about 1 minute. Mix in eggnog and rum just until blended.
• In a separate bowl, combine flour, baking powder, nutmeg, and salt. Mix the flour mixture into the butter mixture gradually until all of the flour has been added and is well blended.
• On the prepaid baking sheet shape each dough half into a long roll, approximately 14 inches long n prepared baking sheet spaced about 3 inches apart. With your hand, press down each roll so that they are about ½″ high.
• Bake for 25 minutes or until golden brown. Remove loaves from pans and place on cooling racks. When biscotti is cool enough to handle, but still warm, using a serrated bread knife cut crosswise slices approximately ½ inch thick.
• Place slices on the cut side back on the baking sheet. Bake for 10 minutes. Turn slices over and bake for another 10 minutes . Transfer to wire racks to cool completely.

Glaze

• In a small bowl, mix together powdered sugar, rum and enough eggnog to reach drizzling consistency.
• Place biscotti pieces about ½-1 inch apart on the baking sheet. Dip the tines of a fork into the glaze, allowing some of the excess to drip off. Hold the fork about 6 inches above the biscotti and sweep back and forth drizzling lines over all of the biscotti pieces. Allow to set.

  Store in an air tight container.