• Start by sifting the almond flour and sugar free powdered sugar into a medium bowl. Set this bowl aside.

  Also, line two baking sheets with parchment paper.
• In a clean mixing bowl and a mixer fitted with a clean whisk attachment, whisk the egg whites and cream of tartar on medium until they begin to foam.

  Slowly add the granulated sugar alternative. Do this one tablespoon at a time, continuing to beat the ingredients.

  You can add the food coloring gel at this time and continue to beat the ingredients until stiff peaks form.

  The batter should appear to be stiff enough to hold its own if it were to be dropped.
• For the next step, we will add the dry ingredients from the first bowl to the mixing bowl. Do this by adding one third of the dry ingredients at a time and using a clean rubber spatula to fold the dry ingredients in.

  When the mixture is able to form a ribbon when it falls off of the spatula you can transfer the meringue to a piping bag fitted with a small round tip.
• Pipe 1” macarons onto your baking sheet, leaving plenty of room between each. Hold each individual tray a few inches off the counter and drop it straight down to release any air bubbles. You may need to repeat this a few times to release the larger bubbles.
• Set the macarons aside to rest for 20-30 minutes or until a skin has formed. You should be able to tap them gently without the meringue sticking to your finger.
• While the macarons rest, preheat your oven to 300F (recommended that you use an oven thermometer).

  Bake the macarons, one tray at a time, on the middle rack. Bake for 12-14 minutes, turning the tray halfway through baking.
• Lastly, allow the macaron shells to cool completely on the pan before assembling the finished product.

Filling

• In a mixer with a paddle attachment, beat together the butter and melted chocolate on medium until light and fluff (about 30 seconds).
• Bump the mixer down to low and add the sugar free powdered sugar. Once the powdered sugar has been fully incorporated bump the mixer up to medium high and beat until the buttercream becomes light and fluffy--about 1 minute.
• Transfer the filling to a piping bag. or zip top bag with a cut corner.
• To assemble the macarons, place the macaron shells in similar sized pairs. Then pipe a small ring of buttercream onto the flat side of one macaron and fill the center. Next, place another macaron shell on top and press down gently, just until the chocolate buttercream reaches the edges.
• Refrigerate the macarons in an airtight container overnight. Lastly, allow the macarons to get to room temperature before serving.