Preheat the oven to 180°C (356°F).
Melt unsalted butter over medium-low heat until it turns brown, then let it cool.
In a bowl, combine cake flour, almond powder, green tea powder, baking powder, and salt.
In another bowl, mix egg whites and sugar until the sugar dissolves.
Add the egg white mixture to the dry ingredients and mix well.
Add the cooled melted butter and gently mix until smooth.
Fill financier molds about 80% full with the batter.
Bake in the oven at 180°C (356°F) for 15-17 minutes, then let cool before serving.