Using a kitchen scale, portion your ingredients into separate bowls.

Using a large mesh sieve, sift the almond flour and powdered sugar together two times.

Place the eggs whites in the bowl of your stand mixer. Using your stand mixer's whisk attachment, whisk the egg whites on medium high speed for about 1 minute. The egg whites should be frothy.

While whisking at medium high, begin to slowly add the granulated sugar to the egg whites, one spoonful at a time until all 50g are added.

Stop the stand mixer and add the orange extract and food coloring. Turn the stand mixer back on and whisk at high speed for about 3 minutes or until stiff peaks have formed. When you stop the mixer and pull your whisk attachment up, the peaks should stick straight up and might have a slight bend at the very top but not at the base. Make sure to stop the mixer and check every so often to make sure you have not overbeaten the meringue.

Remove bowl from the stand mixer once the proper meringue texture is achieved.

Add the orange zest to the meringue. Gently shake the powdered sugar/almond flour mixture into the bowl of meringue ⅓ at a time. After each time, gently fold the dry ingredients into the batter. Do this by making a J or figure-8 shape each time, starting around the outside of the bowl and gently twisting into the middle. It is time to stop folding when the macaron batter is glossy has a "lava-like" thick and flowing consistency. It should drizzle off your spatula in thick ribbons.

Transfer batter into piping bag fitted with a large round tip. Place piping bag perpendicular to your lined baking sheet and pipe by applying gentle pressure to the bag for about 3 seconds. Stop squeezing and quickly pull up the piping bag in a circular motion. Repeat until you've piped all the macaron batter.

Bang each baking sheet on the counter several times to remove air bubbles. Using a toothpick, pop remaining air bubbles on macarons quickly before they begin to dry.

Allow your macarons to sit for 20-40 minutes depending on the humidity of the day. The more humid it is, the longer the macarons need to dry. You will know they are ready when they appear slightly matte and feel dry to the touch.

Bake for 10-15 minutes, rotating the pan in the oven after 6 minutes or so for even baking. Let the macarons cool completely before removing from the baking sheet (they will stick if not completely cool!)

To make the chocolate buttercream, prepare another piping bag with a good tip for piping. Place softened butter into the bowl of your stand mixer. Cream the butter with the whisk attachment for about 2 minutes on medium high speed until smooth and fluffy.

Scrape the sides of the bowl and slowly add the powdered sugar. Whip on medium speed while adding small drops of milk until the desired consistency for piping is achieved. Add the cocoa powder and salt and continue mixing until well incorporated, adding small amounts of milk to adjust the consistency.

Add the chocolate buttercream to the prepared piping bag and pipe into half of the cooled macaron shells. Place other shells on top to create sandwiches.