Prepare 2 or 3 baking sheets with parchment paper, set aside
Prepare a Pastry Bag 18-in. with a large round Pastry Tip, set aside
Sift together the confectioners’ sugar and almond flour in a large bowl, set aside.
Whip the egg whites on medium speed until foamy, about 1 to 2 minutes. Add the sugar 1 tablespoon at a time with the mixer on medium. Add the green Food Coloring.
If you are using the paste colors, wipe it on the bottom of the whip attachment. Add it until you have achieved the color you like. Continue whipping the eggs until they are glossy and hold a stiff peak, about 5 to 8 minutes. When you lift the whip out of the bowl it should hold a straight point.
Add about half of the flour mixture to the egg whites. Using a rubber spatula fold in the flour, and mix in the second half of the flour mixture, just until incorporated.
Fill the pastry bag about 1/2 full with the macaron mixture.
Tap the tray several times on the counter to flatten the macarons slightly and get any air bubbles to the surface. Let the trays sit, uncovered for about 30 minutes so the macarons form a bit of a skin on them. They will
As they are sitting, preheat the oven to 325° and position the oven racks in the top and bottom thirds of the oven.
Place the macarons in the oven and immediately reduce the temperature to 300°F. Bake until the meringue is puffed, but still pale. Switch the racks and continue to bake for a total of about 15 to 20 minutes. If you used a third sheet tray, you will need to preheat the oven back to 325° before you start to bake them. Reduce the temperature to 300° once they are in the oven. (This extra step helps them rise properly.)
Once the macarons are completely cooled, flip half of the them over and pipe on the ganache using a pastry bag and a small round pastry tip. Sandwich together.