1. 1. Prepare your baking pan and oven: Preheat your oven to 325 F (160 C). Line a 9×13-inch baking pan with parchment paper, leaving an overhang on the sides to easily lift the bars out later. This makes cleanup and removal much simpler.

2. 2. Make the graham cracker crust: In a medium bowl, combine the graham cracker crumbs, 1/4 cup granulated sugar, and melted butter. Mix until the crumbs are evenly moistened and resemble wet sand. Press this mixture firmly and evenly into the bottom of the prepared baking pan. Use the bottom of a glass or your fingers to compact it well.

3. 3. Partially bake the crust: Bake the crust in the preheated oven for 8-10 minutes. This helps set the crust and prevents it from becoming soggy. While the crust bakes, move on to preparing the filling.

4. 4. Prepare the cheesecake filling: In a large mixing bowl, using an electric mixer, beat the softened cream cheese and 1/2 cup granulated sugar together until smooth and creamy, with no lumps. Scrape down the sides of the bowl as needed.

5. 5. Add the wet ingredients and spices: Beat in the eggs one at a time, mixing well after each addition until just combined. Then, gradually add the eggnog, vanilla extract, and ground nutmeg. Mix on low speed until the filling is smooth and fully incorporated, being careful not to overmix, which can introduce too much air.

6. 6. Assemble and bake the bars: Pour the cheesecake filling evenly over the partially baked graham cracker crust. Gently tap the pan on the counter a few times to release any air bubbles.

7. 7. Bake the cheesecake bars: Bake for 35-40 minutes, or until the edges are set but the center still has a slight jiggle. Do not overbake; the cheesecake will continue to set as it cools.

8. 8. Cool and chill: Remove the pan from the oven and let it cool completely on a wire rack. Once at room temperature, transfer the pan to the refrigerator and chill for at least 2-3 hours, or preferably overnight, before cutting and serving. This chilling time is crucial for the bars to firm up properly. Before serving, you can optionally sprinkle with a pinch of ground cinnamon.