Preheat your oven to 340 degrees F (170 degrees C).
Cream Salted Butter (300 gram) and Powdered Confectioners Sugar (90 gram) until light and fluffy.
Combine yolks of the Egg (2) into the mixture.
Then, stir in All-Purpose Flour (230 gram) and Corn Starch (90 gram).
Divide the dough into 3 and flavor them accordingly, 1/3 of the dough with Matcha Powder (2 teaspoon) and another 1/3 of the dough with Coffee Emulco (1 1/2 teaspoon) and Unsweetened Cocoa Powder (1 1/2 teaspoon).
Transfer each dough into the respective piping bag with a star tip. Then, pipe out evenly onto a baking tray lined with parchment paper.
Bake it in the oven for 15 to 20 minutes until golden brown.
Let them cool completely before storing it into an airtight container.