1/2cup(1 stick) unsalted buttersoftened to room temperature
2large eggsroom temperature*
Preheat the oven to 350ºF. Spray a loaf pan with nonstick spray. Set aside.
In a medium size bowl, whisk together the flour, baking powder, salt, cinnamon, and nutmeg. Set aside.
In a large bowl with a handheld mixer or the bowl of a stand mixer fitted with the paddle attachment, cream the brown sugar and butter on medium-high speed until light and fluffy, about 2-3 minutes. Add the eggs one at a time, beating until each is incorporated.
Turn the mixer speed down to medium-low and slowly pour in the eggnog. Add the vanilla, and continue to beat until everything is incorporated.
While continuing to beat the mixture on medium-low speed, add in the dry ingredients, stopping when everything is mostly combined. Do not overmix.
Pour the batter into the prepared loaf pan. Bake bread for 40-45 minutes, or until a toothpick inserted in the center comes out mostly clean. Allow to cool completely before serving. Store leftovers at room temperature up to 4 days, or in the refrigerator up to 1 week. Loaf freezes well, up to 3 months. Thaw in refrigerator or at room temperature overnight.
*It is imperative to use room temperature ingredients when working with room temperature butter. Batter blends together much more uniformly when everything is the same temperature.