In a large mixing bowl, combine the almond flour and powdered sugar. Sieve the mixture to ensure there are no lumps.

In another bowl, add aged egg whites and cream of tartar. Whip on medium speed until soft peaks form, about 2-3 minutes.

Gradually add castor sugar to the whipped egg whites, continuing to mix on high speed until stiff peaks form, about 2-4 minutes.

Gently fold the dry mixture into the whipped egg whites in three parts using a spatula until smooth, about 20-25 folds.

Add pink gel food coloring with a toothpick into the batter and mix gently until desired shade is reached.

Prepare a piping bag with a round tip and fill it with the macaron batter. Pipe heart shapes onto parchment-lined baking sheets.

Let the piped shells rest at room temperature for 30-60 minutes until they form a skin and feel dry.

Preheat your oven to 150°C (300°F) and bake the macaron shells for 15-20 minutes, watching for them to rise.

In a small saucepan, heat the heavy cream until just simmering, pour over the chopped white baking chocolate, stirring until smooth. Mix in whole cinnamon hearts and ground cinnamon, set aside to cool.

Once the macaron shells are cool, match them into pairs and fill each shell with the cinnamon chocolate filling, pressing them gently together.