For the Macarons:
Sift the confectioners sugar and almond flour into a bowl.
Add the room temperature egg whites into a very clean bowl.
Using an electric mixer, whisk egg whites. Once they begin to foam add the cream of tartar and then SLOWLY add the granulated sugar.
Add the food coloring (if desired) and vanilla then mix in. Continue to beat until stiff peaks form.
Begin folding in the 1/3 of the dry ingredients.
Be careful to add the remaining dry ingredients and fold gently.
The final mixture should look like flowing lava, and be able to fall into a figure eight without breaking. Spoon into a piping bag with a medium round piping tip and you’re ready to start piping.
Pipe one inch dollops onto a baking sheet lined with parchment paper (this should be glued down with dabs of batter). Tap on counter several times to release air bubbles. Allow to sit for about 40 minutes before placing in oven.
Bake at 300F for 12-15 minutes, rotate tray after 7 minutes. Allow to cool completely before removing from baking sheet.
For the French Buttercream Filling:
Combine sugar and water in medium saucepan. Heat over low heat while stirring until sugar dissolves. Increase heat to medium- high and bring to a boil
Put egg yolks in a stand-mixer fitted with a whisk attachment and beat until thick and foamy.
Cook the sugar and water syrup until it reaches 240 degrees F. Immediately remove from heat. With mixer running, SLOWLY drizzle hot syrup into bowl with yolks.
Continue mixing until the bottom of the bowl is cool to the touch and the yolk mixture has cooled to room temperature.
Add in butter one cube at a time allowing each piece to incorporate before adding the next. Add vanilla and salt. Continue mixing until buttercream is smooth and creamy. (About 5-6 minutes.) Add food coloring if desired.
For Assembly
Pipe your filling onto the back of half the shells. Form a sandwich and repeat. Macarons should be aged in the fridge for 1-3 days for best results. This allows the filling to soften the shells inside.
