First, grab a medium bowl and whisk together your flour, baking soda, baking powder, salt, and half a teaspoon of nutmeg. Set this blend aside for a moment.
Next, in a large bowl, gently cream the softened butter and granulated sugar together using a hand or stand mixer. Beat them until they’re light and fluffy, usually about 2 to 3 minutes, creating a perfect base for your cookies.
Now, introduce the egg, vanilla extract, and eggnog to your creamy butter mixture. Mix until everything is just combined. Don't worry if it looks a little curdled; that’s completely normal and won’t affect your delicious cookies.
Gradually add your dry ingredient mixture into the wet ingredients, mixing just until combined. Be careful not to overmix to keep them tender. Scoop generous tablespoons of dough onto a parchment-lined baking sheet, spacing them out. Bake in a preheated oven at 350°F (175°C) for 8-10 minutes, or until the edges are beautifully golden and the centers are just set. This helps keep them wonderfully soft.
While your cookies cool down, prepare the delightful glaze. In a small bowl, whisk together the powdered sugar, a couple of tablespoons of eggnog, and vanilla extract until smooth. Once the cookies are completely cool, drizzle this sweet glaze over them and finish with a light sprinkle of fresh nutmeg for that signature flavor.