To make the sugar cookies, in a large bowl, whisk together All-Purpose Flour (1 cup), Baking Powder (1/4 teaspoon), Salt (1/8 teaspoon), and Ground Cinnamon (1/4 teaspoon). Set aside.
In a mixing bowl, lightly cream Unsalted Butter (1/4 cup) and Powdered Confectioners Sugar (1/2 cup) until light and pale.
Mix in Egg (1) and Vanilla Extract (1/2 teaspoon).
Throw in flour mixture and mix on low speed until just combined.
Transfer into a cling wrap and let it cool in the freezer for 20 minutes.
Dust your countertop with some flour, roll out your dough until half a centimeter thickness.
Cut out shapes using a Christmas tree cutter that has been coated with flour. Re-roll if needed to repeat.
Transfer into a baking tray lined with baking paper. Let it set in the fridge while you preheat your oven to 350 degrees F (180 degrees C) or 320 degrees F fan-forced (160 degrees C fan-forced).
Bake it in the oven for 10 to 12 minutes.
Let it cool while you make your royal icing.
Make the royal icing. Beat Egg (1) white, Vanilla Extract (1/2 teaspoon), and Salt (1 teaspoon) together until frothy.
Gradually add in Powdered Confectioners Sugar (1 1/2 cup) while beating the mixture on high speed.
Beat on high speed for about 5 minutes until thick, glossy and stiff.
Divide the icing into 4 parts, 1 tablespoon for white, red and yellow icing respectively. Leave the rest for green.
Color them using the Green Food Coloring (to taste), Yellow Food Coloring (to taste), and Red Food Coloring (to taste). Wrap it with cling firm if you are not using any moment as it will dry out.
Transfer your royal icing into a piping bag individually. Pipe an outer layer of green icing for each Christmas tree. This is called outlining.
Decorate the cookies with the different color of icing to your liking. Let it set.
Make the cookie pots. In a bowl, whisk together All-Purpose Flour (1 1/4 cup), Ground Cinnamon (1/4 teaspoon), Fine Salt (1/8 teaspoon), and Baking Soda (1/4 teaspoon).
Preheat oven to 360 degrees F (180 degrees C).
In a mixing bowl, cream together Unsalted Butter (1/2 cup), Granulated Sugar (1/4 cup), and Brown Sugar (1/4 cup) until light and fluffy.
Add in Egg (1) yolk and Pure Vanilla Extract (1 teaspoon).
Gradually mix in some flour mixture until combined. Fold in Dark Chocolate (3 tablespoon).
Transfer tablespoonful worth of dough into mini cupcake pan.
Bake it in the oven for 8 to 10 minutes.
Once it’s out from the oven, immediately coat the end of every Christmas tree with melted chocolate and squash it into the center of every pot cookies.
Let it cool in the fridge and serve. Or wrap it up as a Christmas gift.