• Preheat the oven to 150 degrees Celsius fan-assisted. Line a baking tray with baking sheet. *
• Sift the icing sugar and almond flour together into a bowl, using a spatula to assist the sifting.
  
• Prepare the meringue.

  Beat the egg whites in a large mixing bowl with a mixer, gradually from low speed to medium-high speed. Once the egg whites are white and foamy, start adding the white sugar in - one tablespoon at a time, at 15-seconds intervals.
• Once the mixture reaches soft peaks, add in a few drops of food colouring. Continue beating until stiff peaks.
• Fold half of the dry ingredients into the meringue. Once incorporated, add the remaining half and fold. ** 
• Prepare piping with a piping bag and a round nozzle tip. Pipe the batter onto the baking sheet, leaving at least half an inch between each shell. ***
• Tap the baking tray on the counter top a few times to remove air bubbles. Leave the piped batter to rest for 25 minutes. 
• Once the batter has formed a dry surface layer, the macarons are ready to be baked. This can be test by gentle touching a macaron side to ensure no batter sticks onto your finger.
• Bake them in the preheated oven for 16 minutes. Once the baking is done, allow them to cool on the tray for 10 minutes. Transfer the shells to a wire rack to cool completely before filling.

Baileys Buttercream Filling:

• Heat the heavy cream, Baileys and espresso in a saucepan over medium heat. Remove from heat just before it begins to boil.
• Pour the hot cream mixture over the chocolate chunks. Leave for 1-2 minutes before stirring to melt the chocolate. Leave aside or in the fridge for the buttercream to firm up.

Assembling the macarons:

• Pair up the macarons by their size. Pipe the fillings on one of the macaron and sandwich them together. The macarons are ready to be served, otherwise they can be kept in the fridge up to 3 days.