Preheat your oven to 350°F (175°C) and generously grease your mini loaf pans with butter or cooking spray, making sure to coat the corners and edges well so the loaves release easily after baking. While the oven preheats, let your eggs sit at room temperature if they aren't already—this helps them incorporate more smoothly into the batter and creates a better crumb structure.

In a medium bowl, whisk together the flour, baking powder, salt, cinnamon, nutmeg, and allspice. Make sure to break up any clumps in the spices and distribute the leavening agent evenly throughout the flour—this ensures your loaves will rise consistently. I like to sift these together if I have a sifter handy, as it creates a lighter, more tender crumb in the finished loaves.

In a separate bowl, whisk together the room-temperature eggs, chilled eggnog, sugar, cooled melted butter, vanilla extract, and rum extract until well combined and slightly frothy. The sugar should be mostly dissolved and the mixture should look relatively uniform. I find that whisking vigorously for about 30 seconds helps emulsify the butter and eggnog, which creates a more tender, moist loaf.

Pour the wet ingredient mixture from Step 3 into the bowl with the dry ingredients from Step 2. Using a spatula or wooden spoon, gently fold the ingredients together until just combined—stop as soon as you don't see streaks of flour. Overmixing develops gluten and makes the loaves tough, so resist the urge to stir too vigorously; a few small lumps are perfectly fine and will disappear during baking.

Divide the batter evenly among your prepared mini loaf pans, filling each about two-thirds full. Place the pans in the preheated oven and bake for 30 minutes, or until a toothpick inserted into the center of a loaf comes out clean or with just a few moist crumbs. The tops should be golden brown and spring back lightly when touched.

Remove the loaves from the oven and let them cool in the pans for 2-3 minutes—this allows them to set just enough to hold their shape without becoming too firm to release. Then turn them out onto a wire rack to cool completely. The loaves can be enjoyed warm or at room temperature, and they actually taste even better the next day as the flavors meld and deepen.