Place room temperature egg whites in the bowl of a clean mixer.
Add in cream of tartar and whisk on high to soft peaks. Turn mixer on low and continue to run mixer while you prepare the sugar mixture.
Put sugar in a heavy pot and add in water. Brush down the sides of the pot with a pastry brush that has been dipped in water. This is to wash away any sugar crystals. DO NOT mix the sugar mixture, it's not necessary and can cause crystallization. Place your candy thermometer in sugar mixture. If your thermometer is digital, set the alarm to 235°
Once the sugar reaches 235° carefully pour the hot melted sugar into the bowl of whipping egg whites in a steady stream. Make sure the mixer is running on medium speed while you are doing this. When you have poured all of the sugar into the whipped egg whites, turn the mixer on high and continue to whip until the egg whites have reached a stiff consistency.
Combine almond flour, powdered sugar, salt, pumpkin pie spice and cinnamon in the bowl of a food process. Pulse several times to create a fine powder.
Pour the almond flour/sugar mixture into a sifter and carefully sift into a large bowl. Discard any remaining bits of almond flour that did not easily sift through as this is too course for macarons and will yield a lumpy texture.
Add in egg whites into the center of the almond flour mixture. Use a rubber spatula to stir the meringue down and up gently, almost as if you're writing a "J" in the mixture. Bring the spatula down and up through the ingredients. The whipped egg whites will gradually pick up the almond flour mixture. Fold gently until the mixture drops from the spatula in a ribbon type manner. This should only take about 6-8 stirs.
DO NOT OVER MIX. If you intend to add color, it's best to add the color before you have completed the mixing process to prevent over-mixing.
Place macaron mixture into a piping bag with a large round cake nozzel. Pipe onto a parchment lined sheet tray.
Slam tray on the counter several times to remove any air bubbles. Don't worry, you won't do any damage to the macarons.
Allow macarons to sit uncovered on the counter for approximately 20-30, or until a skin is formed. You will be able to touch the tops of the macaron and it will not feel sticky.
Bake macarons in at 235° for approximately 18 minutes. Convection ovens are best, however, you can bake in a standard oven without any issues.
The cookies are done when you can easily remove them from the parchment paper. If they stick to the paper, they are not done. Be patient as these cookies are very temperamental.