• Line an upside-down pan with a silicone baking mat and fit a piping bag with a small round tip, set them both aside.
• In a large bowl, sift together the powdered sugar and almond meal, until no lumps remain. Set aside.
• Add the room-temperature egg whites to a bowl of a stand mixer. Whip the egg whites on medium speed for 2-3 minutes, until white and foamy, then add the cream of tartar.
• Slowly add in the granulated sugar and then increase the speed to medium-high. Mix for 5-6 minutes until medium peaks, then add the food coloring. Continue whipping for 1-2 minutes longer or until stiff peaks form.
• Use a rubber spatula to gently fold the almond meal/powdered sugar mixture into the stiff egg whites. Slowly fold and mix the batter until smooth. The batter is ready when it flows slowly in ribbons off the spatula and you can draw a figure 8.
• Line an upside-down baking tray with a silicone baking mat. Fill a piping bag with a small round piping tip and pipe the batter over the top of the tray into 1 ½ inch rounds spaced 2 inches apart. Tap the baking sheet on the counter to remove any air bubbles. You can pop any bubbles with a toothpick. Mix together the sugar and pumpkin spice and sprinkle it generously over the tops of the shells.
• Let the macarons sit at room temperature to form a skin, anywhere from 30-60 minutes. While the macarons are resting, preheat your oven to 300 F/150 C.
• Bake each tray for about 13-14 minutes. The macarons are done baking when you gently touch the top of the shell, it should just barely budge from the foot. Allow them to cool completely on a wire rack before filling.

Making the Buttercream

• In a stand mixing bowl, add the cold cream cheese and mix with the paddle attachment until smooth, about 20 seconds. Add the soft butter and mix on medium-low speed for 30-60 seconds until they are both combined.
• Add the powdered sugar in a little bit at a time, mixing well after each addition. Scrape down the bowl with a spatula, then whip on high speed for 30 seconds until the buttercream is light and fluffy. Add the pumpkin puree and pumpkin spice and mix on medium-low to combine. Scrape down the bowl and mix again to make sure everything is combined.

Assembling

• Fill a piping bag fitted with a small round tip with the pumpkin buttercream. Pipe a dollop onto one-half of the shells and then sandwich the filling with the other half. Keep in the fridge in an airtight container overnight or at least for 12 hours to mature and soften, then enjoy!