Preheat the oven to 375 degrees. Line muffin pans with paper liners.
In the bowl of your stand mixer, add the eggnog, butter, eggs and vanilla and mix on low speed.
In a medium bowl, whisk together the flour, sugar, baking powder, cinnamon, nutmeg and salt.
Slowly add in the flour mixture to the eggnog mixture until just combined.
Scoop batter into the prepared muffin pans, filling each halfway full.
Prepare the crumb mixture by whisking together the flour, brown sugar, cinnamon and salt in a bowl. Add in the butter and use two forks or a pastry cutter to mix the butter into the ingredients, until it forms a crumbly mixture.
Add the crumb mixture on top of the muffin batter.
Bake for 17-20 minutes or until a toothpick inserted in the center comes out clean.
Remove from the oven and allow muffins to cool in the pan for 5 minutes before transferring to a wire rack to cool completely.
Sprinkle powdered sugar on top. Muffins will keep for 2-3 days in an air-tight container.