Matcha-flavored Palmier cookies

Ingredients:

• 3 tablespoons unsalted butter, room temperature
• 0.5 cup + 3 tablespoons sugar
• 2 tsp. matcha green tea powder
• 1 large egg yolk
• 2 tsp premium flour
• 1 teaspoon of milk
• 0.5 tsp vanilla extract
• Green gel food coloring
• 1 sheet of frozen puff pastry (half a 0.5 kg package), thawed

Preparation:

1. Position oven racks in the upper and lower thirds of the oven; preheat to 200°C (400°F). Line 2 baking sheets with parchment paper. In a bowl, combine the butter, 3 tablespoons sugar, matcha, egg yolk, flour, milk, and vanilla with a rubber spatula until smooth. Stir in the green food coloring, adding 1 drop at a time until the color is bright green.
2. Spread the remaining 1/3 cup sugar on a clean work surface. Unfold the puff pastry and place it on top of the sugar, pressing gently to adhere. Flip it over and press to coat the other side. Roll the dough into a 12-inch square. Spread the matcha mixture in a thin, even layer over the dough, leaving about a 1/4-inch border. Using your hands, roll one side of the dough toward the center, then roll the opposite side toward the center so the two rolls meet in the middle (if the dough seems soft, place it in the freezer for 15 minutes).
3. Trim the ends of the dough with a knife, then cut into 1 cm thick slices. Place them cut-side down on the prepared baking sheets, 5 cm apart.
4. Bake until the cookies are golden brown and crisp around the edges, 14-16 minutes. Flip them with a thin spatula, switch the baking sheets, and bake until the other side is golden brown, another 6-8 minutes. Let cool completely on the baking sheets.