Grind up almond flour in a dry food processor and sift through a sieve. Do not force it through the sieve.
Sift confectioners sugar and spices into almond flour with a sieve and a whisk.
Beat egg whites and cream of tartar on medium / high. Slowly add in granulated sugar.
When the soft peak stage is reached add food coloring and vanilla. Mix till stiff peak stage.
Add about ¼ the dry ingredients to the egg whites. Fold with spatula till combined.
Then add the rest of the dry ingredients and gently macaronage (fold) till “lava” texture is reached. The batter should make ribbons that don’t break when you lift the spatula. Try making a figure 8.
Line 2 cookie sheets with parchment, using a tiny dab of batter on each corner as glue.
Add batter to a piping bag using a plain round tip.
Pipe about 1 ½” circles, holding the bag perpendicular to the cookie sheet. To break off batter, make a little swirl motion on top.
Bang sheet on counter to get rid of bubbles and to help tops get smooth.
At this point add a light dusting of nutmeg or cinnamon.
Preheat the oven to 300 degrees F.
Let sit for 45 - 60 minutes on the counter uncovered. You should be able to touch the macarons, there will be a skin formed on top.
Bake for 10 - 15 minutes. You should be able to see the “feet”.
Let cool completely before piping in the filling. Make little macarons sandwiches by matching up with the same sized tops and bottoms.
EGGNOG FILLING
In a small saucepan, add eggnog, sugar, cornstarch, spices, and yolks. Whisk ingredients until there are no lumps.
Turn heat on to medium-low, constantly whisk custard until it starts to bubble, lower heat. Be careful not to burn, don’t leave to do something else. Keep cooking and stirring for one minute on low.
Turn off heat, add in vanilla, mix in completely. Strain custard through a sieve and set aside eggnog custard to cool.
Whip butter in a mixer until light, add in cooled custard. Keep whipping until fluffy and well combined.
Put icing in a piping bag and pipe onto macaron shells.
Store in the fridge. Cookies taste best the next day.