Pulse almond flour and powdered sugar in a food processor or blender to combine well.
Beat egg whites in a clean bowl of a stand mixer until foamy. While mixer is running, slowly add 110 grams regular sugar to eggs. Beat until stiff peaks.
Remove bowl from stand mixer and fold in almond flour mixture in three batches. Continue to stir mixture with spatula, pressing mixture against the sides of the bowl to deflate egg whites a bit. Batter is ready when if you make a figure 8 in batter, it slumps slowly back together and flows a bit like lava.
Transfer mixture to a piping bag fitted with a large round tip. Pipe round circles of batter onto a baking sheet lined with parchment paper. Try to make them the same size. (there are templates you can place under your parchment to make sure they're the right size and spaced out far enough from each other... as i too often do with too many things, i just eyeballed it.)
Once the tray is full, take out any aggression by banging the tray on the counter a few times to knock out bubbles and flatten batter circles. Top with a few Gold Sugar Pearls, if desired. Allow trays to sit for 30 minutes or until batter is dry to the touch. This forms a skin on the surface of the macarons. Meanwhile, preheat your oven to 330°.
Bake macarons at 330° for 11-13 minutes. Allow them to cool completely.
To Make Champagne Buttercream:
Beat softened butter until creamy. Add powdered sugar and beat until combined. Add Champagne to mixture and beat until smooth.
Transfer to a piping bag and pipe Champagne Buttercream onto a macaron half; top with another macaron half to make a sandwich. Store in fridge for a few days or in the freezer for even longer.