**Preheat the Oven:** Preheat your oven to 350°F (175°C). Grease and flour a 9x5-inch loaf pan or line it with parchment paper.

**Prepare the Dry Ingredients:** In a medium bowl, whisk together the flour, baking powder, cinnamon, nutmeg, and salt. Set aside.

**Make the Batter:** In a large bowl, cream together the softened butter and granulated sugar using an electric mixer until light and fluffy. Add the eggs one at a time, beating well after each addition. Stir in the eggnog and vanilla extract.

**Combine Wet and Dry Ingredients:** Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix.

**Bake the Bread:** Pour the batter into the prepared loaf pan and spread it evenly. Bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean. Let the bread cool in the pan for 10 minutes before transferring it to a cooling rack to cool completely.

**Prepare the Glaze:** In a small bowl, whisk together the powdered sugar, eggnog, and vanilla extract until smooth.

**Glaze the Bread:** Once the bread has cooled, drizzle the glaze over the top of the loaf, allowing it to gently cascade down the sides.

**Serve:** Slice the bread and serve.