Instructions: Warm the oven up to 325F 165C and put parchment paper on a baking sheet. Mix the matcha powder, salt, and gluten-free all-purpose flour in a bowl with a whisk. Melt the butter and mix it with the powdered sugar in a different, bigger bowl until the mixture is light and fluffy. Mix the vanilla extract into the butter mixture until it's fully mixed in. Slowly add the dry ingredients to the wet ones and mix them together until a dough forms. Roll or cut the dough into a rectangle or log on a piece of parchment paper. To make it firmer, wrap the dough tightly in parchment paper and put it in the fridge for 30 minutes. When the dough is firm, take it out of the plastic wrap and cut it into cookies of any thickness you like. Spread the cookies out on the baking sheet that has been prepared. After the oven is hot, bake for 12 to 15 minutes, or until the edges are starting to turn golden. After taking the cookies out of the oven, let them cool for a few minutes on the baking sheet. Then, move them to a wire rack to cool all the way down.