Prepare your baking sheets (you'll need 3). If you have silicone mats with the circles on them for piping macarons, great. If not, not to worry. Take a 1-½" cookie cutter and draw circles using a black marker, 2" apart from each other. This sheet will be your template, you'll need to line your baking sheets with parchment paper (you won't actually use the paper with the drawing, that is used as a template underneath the paper.
Sift the almond flour, 2 cups of powdered sugar and pumpkin pie spice into a large mixing bowl, then set aside.
Beat the egg whites in the bowl of your stand mixer on medium speed until soft peaks form. Add granulated sugar gradually, until stiff peaks have formed.
Add the orange food color, just a few drops should be fine then beat until incorporated.
Add ⅓ of the almond flour mixture to the egg whites. Using a spatula carefully fold the flour into the egg whites.
Repeat with another ⅓ of the almond flour mix, then again with the last.
Add the macaron mixture to a piping bag fitted with a Wilton 1A tip.
Place the parchment paper with the circles on a baking sheet then place another sheet over the top. You should be able to see the circles underneath easily. Pipe the macaron mixture onto each circle, using them as a guide to how much. Try not to go over the lines to keep a uniform size.
Once you have a tray completed remove the stencil from underneath the parchment paper and tap the baking sheet a few times on your kitchen counter to break any air bubbles.
Allow to sit at room temperature for about 60 minutes, to dry a little. They'll be ready to bake when you can touch the top of a macaron and it not stick to your finger.
Heat oven to 325°F and bake each sheet for 13-15 minutes. Depending on how even your oven bakes you may need to rotate your baking sheet half way through cooking.
Remove from the oven and allow to cool completely. Repeat with the other baking sheets.
While the macarons are cooling add the softened butter, 2 cups of remaining powdered sugar, vanilla and cream to a large bowl and beat until totally combined. Add this buttercream to a piping bag with a 1A tip and once the macarons have cooled completely pipe onto cookies and top with another cookie to make a complete pumpkin spice macaron.
Notes
Aging your egg whites is going to give you best results. Once you have separated the egg whites from the yolks cover and keep in the refrigerator for a day or two. It'll dry the whites out a good bit.If you don't have piping bags/tips then you can use a resealable bag and just snip the corner off to pipe.