Beat egg whites until foamy, then add white sugar and beat until stiff peaks form.
Sift almond flour and powdered sugar in large bowl.
Fold flour/sugar mixture into the egg white mixture. (about 50 folds! Your batter should be marshmallowy and flow slowly. You're trying to crush the air bubbles in so your cookies aren't holly when baked)
Transfer batter to a pastry bag.
Pipe out one inch rounds on a baking sheet lined with silpat or parchment paper. Lift the baking sheet about six inches off the counter, drop it, then repeat. This is done to remove unwanted air bubbles.
Allow to rest uncovered for about 40 minutes.
Bake at 300F for 20 minutes.
For the Buttercream
Cream the butter and pumpkin puree.
Add in the sugar and spices.
Mix well and scrape down side of bowl.
Add vanilla and mix well.
For the Assembly
Pipe a dollop on the back of a cookie and sandwich together.
Fold the macaron batter until the consistency becomes marshmallowy. When it drizzles back into the bowl you should see a rope of it for a few seconds before it melts back into itself.
Age your egg whites! Separate the eggs, place the whites in a clean glass, cover with plastic wrap and let them hang out in the fridge for a few days before using. This will dehydrate them and make them perfect for macarons.
Give the pan of pipes macaron shells a few good strong taps on the counter to dislodge any air bubbles.
Before you bake them, leave the piped macarons out to harden until they are dry to the touch.
Make sure your eggs are room temperature!
Macarons should be aged at lease a day in the refrigerator. This gives the filling some time to soften the inside of the cookie and create that perfect play of textures you'll find in a macaron.