Preheat oven to 275°F. Lightly oil a baking sheet and line with parchment paper.
Sift the almond flour and powdered sugar. Add one egg white and vanilla extract (or other flavor) and mix to a smooth batter.
Begin to whip the remaining three egg whites on low until foamy. Slowly begin to increase the speed to medium. When very soft peaks are beginning to form, slowly add the granulated sugar. Increase the speed to high and let the whites and sugar continue to whip until glossy, very stiff peaks form.
Using a rubber spatula, fold 1/3 of the whipped whites into the almond meal batter until well combined. If you wish to add food coloring, do so at this time. Gently fold in the remaining whipped whites, trying to maintain as much volume as possible.
With a piping bag or a small teaspoon, place quarter-size dollops of macaron batter on the lined baking sheets. The batter should be soft and pliable but still hold its shape on the baking sheet.
Lightly tap the baking sheet on the counter to work out any large air bubbles. Sprinkle with any toppings, if desired. Let the macarons sit at room temperature for 15 minutes to form a crust.
Bake for 5 minutes, then rotate the sheet half way and bake for an additional 5 minutes. The macarons should look dry on top.
Let cookies cool to room temperature. If you find that they stick to the pan, immediately upon removing them from the oven, lift the parchment and lightly spray the baking sheet only with a light mist of water.
Macarons can now be filled with your choice of filling (French buttercream, jam, ganache, frosting, nut butters, etc), topped with a second macaron and decorated as desired (dusting of cocoa powder, powdered sugar, luster dust, gold leaf, etc.).
These cookies can be kept in an airtight container for two to three days or frozen if left unfilled.