Mix the green tea powder and sugar well in a bowl.
Add butter and condensed milk to a pot and melt over low heat.
Add the green tea mixture to the melted butter and condensed milk, then stir well.
Cook over low heat, stirring for 5-7 minutes until it becomes sticky.
Pour into a flat mold, let it cool at room temperature, then set in the refrigerator.
Cut into bite-sized pieces.