Line 2 pans with parchment paper.
Sift the almond flour and powdered sugar together and set aside.
Mix the egg whites, granulated sugar, vanilla, nutmeg and kosher salt on low for 3 minutes, then beat on medium speed for 3 minutes and finally on high for 3 minutes. The meringue should be very stiff.
Add the almond and powdered sugar mixture and fold it into the meringue until it has deflated. It should look like molten lava that will hold its shape for a bit and then melt into the mixture.
Pipe the batter into small circles on the parchment paper. Sprinkle with cinnamon.
Hold the pan and firmly smack it against the counter a couple of times, turn the pan and smack it again to remove the air bubbles.
Bake at 300 degrees for about 18 minutes or until the macarons can be easily removed from the parchment paper. If they stick or the shell comes off the but bottom sticks, bake them a little longer.
Cool completely on the pan and then remove to add the eggnog frosting.