Divide the egg whites into 2 bowls of 75 g each. Set aside one bowl and sift the almond meal and the powdered sugar in the other. Add the matcha powder and a small quantity of green food colouring. Mix with a rubber spatula until you get a thick almond paste.
Combine the water and the granulated sugar in a small saucepan and set it on the stove on medium heat. Have the bowl with the egg white at hand, and the mixer ready. Check the temperature of the sugar syrup with a candy thermometer and when it reaches 110°C start beating the egg whites. Continue cooking the syrup, you need to bring it to 121°C. Since it's safer to have a couple degrees less, I always set my thermometer to 118°C to have the time to take it away from the stove and pour it into the whisked egg whites. Pour the hot syrup in one thin stream always mixing. Keep mixing until the meringue reaches room temperature.
When the meringue has cooled to room temperature, add the almond paste to the meringue bowl in two batches. Incorporate the almond paste gently and firmly at the same time, working the mixture with the spatula against the sides of the bowl. This helps to get rid of excess air in the batter. Stop the moment you see that the mixture is smooth and clump free.
Transfer the batter to a piping bag and pipe small circles onto a tray lined with parchment paper. The macarons need to be quite spaced out as they tend to grow larger as the batter sets. Let rest for 30 minutes.
When the surface of the macaron shells is dry to the touch, bake them in the preheated oven at 145°C for 18 minutes. Remove the parchment aper sheet from the hot baking tray as soon as you take the shells out of the oven. Let the macarons cool completely, then fill and sandwich two shells to create beautiful macarons.
