Sift together the oat flour and the powdered sugar into a medium bowl. Set aside.
126 grams oat flour, 126 grams powdered sugar
Beat the egg whites in the bowl of a stand mixer fitted with the whisk attachment until frothy. Add the cream of tartar and continue beating the egg whites while slowly adding the granulated sugar one spoonful at a time.
Add the vanilla and red no taste food coloring gel until a vibrant red color is achieved. Continue beating until stiff peaks form.
1 teaspoon vanilla extract, red no taste food coloring gel
Using a large rubber spatula, fold ⅓ of the dry ingredients into the meringue, then fold in the remaining dry ingredients until the batter almost reaches the "figure 8" stage.
Transfer the batter to the piping bag fitted with a medium round tip.
Pipe 1-inch circles onto a macaron mat on top of an upside down half sheet pan. Slam the pan on the counter several times to force air bubbles to the surface. Use a toothpick or scribe tool to pop bubbles and smooth over the resulting hole.
Repeat this process with the second pan. You will not fill the entire mat.
Allow the batter to rest at room temperature for about 40 minutes, or until the surface has dried enough that if you gently touch your fingertip to it, the batter will not stick. Meanwhile, preheat the oven to 300°F.
Bake the first tray of shells for 12-15 minutes, rotating half way through baking time. Allow the shells to cool on the mat at room temperature. Bake the second tray and allow them to cool as well.
Once the shells have fully cooled, either fill them immediately or store them in a single layer in an airtight container in the refrigerator until you are ready to assemble.
Assemble the Macarons:
Pair up the cooled shells by size.
Fit a disposable piping bag with a round or decorative tip and fill with buttercream of choice.
Pipe a large mound of buttercream into the center of the flat side of each of the bottom shells.
Pick up the top shell by the edges and carefully press on top of the buttercream. Repeat with the remaining pairs.
Add the Royal Icing Decorations:
Prepare outline consistency black, white and gold colored icing. Transfer each to a piping bag and secure the opening.
Start with the black icing by snipping off a very tiny opening in the tip of the of the bag. Pipe a small amount out on a plate or paper towel to get an idea of the pressure required to pipe.
Pipe the outline of a thin belt across the lower third of a macaron, quickly filling in the thin rectangle with black to create a solid black belt. Repeat this process with all of the macarons.
Snip off a small opening in the bag of white icing. Pipe 3 evenly-spaced buttons down the center of the macaron above the black belt.
Allow the belts to dry at room temperature for several hours to set the icing before adding the gold buckle. The black icing doesn't need to be fully hardened, just dried on top so the gold icing will not mix into it.
Snip off the tip of the gold icing. Pipe a little out onto a plate, carefully pipe a small rectangle on top of the center of the belt, then add a small line on the right side of the rectangle. Repeat this with all of the macarons until they have all been decorated.
Store the macarons at room temperature in an airtight container until the gold icing has fully dried. The time this takes will depend on the temperature and humidity of your workspace, but it can take up to 16 hours. You can allow it to dry overnight.
Paint the Belt Gold:
Tap some gold dust into a well of the paint palette. Use the transfer pipette to add some of the clear alcohol to the luster dust and use the paintbrush to mix it into a smooth suspension. You want it to be thin enough to paint on the icing but thick enough so it doesn't run off the icing. Add more gold dust if it is too thin and more alcohol if it is too thick.
Stir the gold suspension again with the paintbrush, then remove the bristles from the liquid and press them to another well in the palette to run off the excess liquid.
Very carefully paint the liquid gold onto the gold icing buckle, dipping the paintbrush back into the liquid gold to get more as needed.
Repeat this process with all of the macarons. The alcohol will evaporate quickly, so the macarons will be ready to store after about 10 to 15 minutes.
Notes
I highly recommend weighing the ingredients listed in grams with a digital kitchen scale. French macarons are notoriously finicky and require precise measurements.Use cracked whole eggs, not store bought egg whites. 100 grams of egg whites (to make both green and pink shells) is the equivalent of the whites from about 3⅓ large eggs."Macaronage," the process of folding the dry ingredients into the meringue, is the trickiest step of macaron making. The batter will be too thick if you under mix it or too thin if you over mix it. I refer you to two resources with visuals as to when the batter is ready to be piped: America's Test Kitchen and Le Cordon BleuEasy Vanilla Buttercream recipe HEREEasy Royal Icing recipe HEREStore the cookies in an airtight container in the refrigerator for a few days to allow them to mature and improve in texture. If refrigerated, allow the cookies to come to near room temperature before serving so the buttercream can soften. Unfilled shells or assembled macarons can be frozen.Nutritional information is only an estimate and will vary based on your ingredients and substitutions. The information for this recipe is only for the shells.You're Gonna Bake It After Allbakeitafterall.com