Preheat the oven to 170C
Cut the croissants in half lengthways.
Prepare the glaze by combining the sugar and boiling water in a bowl and setting aside to dissolve.
Prepare the frangipane but beating together the butter, sugar and almond meal. Once fully incorporated, add the egg and matcha and mix until smooth.
Brush the croissants inside and out with the glaze.
Add about a tablespoon of frangipane to the bottom half of the croissant. Sandwich the top layer back on and pipe another layer of frangipane on top.
Sprinkle a generous amount of almonds on top of the croissants.
Place in the preheated oven for around 10-12 minutes, or until golden on top and the filling warmed.
Prepare the topping by combining sieved icing sugar and matcha in a bowl.
Allow the croissants to cool for at least 10 minutes, the dust liberally with the matcha icing sugar mixture.