In a large bowl, sift together almond flour and confectioners' sugar.
In the bowl of an electric mixer with the whisk attachment or in a large bowl with a hand mixer, beat egg whites on medium speed until they're foamy. Add cream of tartar and salt.
Turn mixer back on to medium and while running, add in about 1 tablespoon sugar at a time. Increase mixer speed to medium/high and beat until soft peaks form. Add in mint extract and vanilla and continue beating until stiff peaks form.
Remove bowl from mixer and sift almond flour and confectioners' sugar into the bowl with the egg whites. Then, using a rubber spatula, gently fold ingredients together by scraping the sides and bottom of the bowl and folding the meringue up and over and pressing down. Continue this motion while turning bowl. As you mix, the batter will begin to thin out. You want to keep folding until the batter drops from the spatula like "molten lava" (it should flow) and is glossy.
Place a pastry bag fitted with a large round tip (I use Wilton 1A) in a tall drinking glass and fold over the top of the bag. Dip a pastry brush or paintbrush in the green food coloring and starting inside the pastry tip, brush a stroke of food coloring from the tip to the top of the bag. Repeat three more times. Fill the bag with the macaron batter.
Line two baking sheets with parchment paper and set template underneath (see notes for template printout). Holding the pastry bag vertically, pipe evenly sized rounds onto the baking sheets. Batter will spread, so only pipe to the edge of the center circle on the template. Note that you want your rounds to be 2 inches. Gently tap the bottom of the baking sheets on counter to eliminate any air bubbles in the batter.
Let baking sheets sit out for 45-60 minutes to allow macarons to dry out. In the meantime, pre-heat oven to 300 degrees.
Bake macarons on middle rack for 15-18 minutes, until macarons are firm to the touch and have risen to form a foot. Let macarons cool completely on baking sheets.
Lightly brush gold powder over the tops of macaron shells, if desired.
Put Baileys buttercream in a pastry bag and pipe about 2 teaspoons on the bottom of a shell. Place another shell on top and push together.