Pumpkin spice latte macarons are a fun take on a classic fall coffeehouse drink!
Sift together the almond flour, pumpkin spice, and confectioner's sugar into a mixing bowl. Top with 55 g egg whites and gel color if using. Do not mix.
While the macarons are baking, make the filling.
Bring a small saucepan of water to a simmer over medium heat. Be sure the water level is low enough that when you place your mixer bowl over the sauce pan, the water does not touch the bottom of the bowl.
In the clean and dry bowl of your mixer, combine the egg whites and granulated sugar. Fit your mixer with the whisk attachment. Place the bowl over the simmering saucepan of water and stir constantly until the sugar has dissolved into the egg whites (about 3-5 minutes). Once the sugar has dissolved, immediately remove the bowl and place in the stand mixer. Slowly work up to a medium high speed and mix until the egg whites and sugar begin to turn white and the outside of the bowl is no longer very hot to the touch.
Add in the espresso powder and then add the softened butter 1 tbsp at a time. Increase mixing speed to high and continue mixing until the filling is glossy and comes together. This can take up to 10 minutes depending on the temperature of your ingredients.
When the shells are cooled, pair them together on the cooling rack. Pipe a bit of filling on one side of the macaron and then top with the other.
Allow the macarons to rest in the refrigerator in an airtight container for 24 hours before serving (ideally). Remove from the refrigerator a few minutes before eating to allow the filling to soften.