For the Macarons

1. Up to 5 days before making macarons, separate the egg whites, cover loosely with a paper towel, and store in the refrigerator. The night before making macarons, set them out on the counter to come to room temperature.
2. The next morning, place almond flour, powdered sugar, and the contents of a vanilla bean into a food processor and process until fully combined. Move to a large bowl and whisk in one teaspoon of cocoa powder for chocolate macarons, or one teaspoon of powdered food coloring for colored macarons. Leave plain for vanilla macarons. Whisk to combine, then sift and set aside.
3. With a mixer, whisk the egg whites on medium-high speed until foamy. Add in granulated sugar and continue whisking until the the egg whites have stiff peaks. Add the egg whites to the flour and fold to incorporate until the mixture is just smooth, using no more than 50 strokes. Fit a pastry bag with a large round tip, and fill with macaron batter. Pipe approximately 1-inch circles onto a baking sheet lined parchment paper. Let the batter rest on the pan at least 30 minutes before baking, to form a strong skin to help keep the macarons from cracking in the oven.
4. Bake the macarons at 280 degrees F for 15-20 minutes directly in the middle of the oven. To test for doneness, gently touch the top of a macaron to make sure it’s dry. Then gently try to lift the macaron from the parchment paper. If it comes away pretty easily, they’re done. If it doesn’t come up and the top breaks away, they need to cook longer. Keep checking on them every two minutes until the bottom is dry. Once removed from the oven, allow the macarons to rest on the pan for 10 minutes to finish cooking before trying to remove. Cool completely before frosting.

For the White Chocolate Peppermint Buttercream

Place the butter, sugar, melted white chocolate, milk and vanilla in a large mixing bowl. Beat on medium speed until smooth and creamy, about 3-5 minutes. Add crushed peppermint and beat until fully combined.

For the Eggnog Marshmallow Fluff

Place butter, sugar, marshmallow fluff, eggnog, and vanilla in a large mixing bowl. Beat on medium speed until smooth and creamy, about 3-5 minutes.

For the Spicy Milk Chocolate Mocha Ganache

Place chocolate chips in a glass or heat-proof bowl. In a medium saucepan, whisk the heavy cream, vanilla, instant coffee power, cinnamon, allspice, cloves, and nutmeg and bring to a simmer. Pour over the chocolate chips, let sit for 5 minutes, then whisk until completely smooth. Chill in the fridge for 1 hour or until the ganache reaches a thick, frosting consistency.

For the Simple Syrup

Bring the sugar and water to a boil until the sugar dissolves. Remote from heat and cool. Brush over the tops of the macaron shells with a pastry brush and sprinkle with glitter.