Combine 1 ½ cups of all purpose flour, 1 ½ tbsp of matcha powder, 1 tsp of baking soda, and ¼ tsp of salt in a bowl. Set aside. Make sure to sift the matcha powder to prevent clumping.
In a separate bowl, whisk together ½ cup of unsalted butter and 1 ⅓ cups of light brown sugar.
Add the egg and 1 tsp of vanilla extract. Mix well.
Combine the wet ingredients with the dry ingredients from step 1.
Using a 2 tbsp (#40 cookie scoop), scoop the dough onto a baking sheet. Cover and let it cool in the fridge for 2 hours.
Preheat the oven to 350 degrees F (177 degrees C). Cover 2 baking sheets with parchment paper. Pour 1/4 cup of granulated sugar into a bowl.
Now it's time to form the cookies! Take out about half of the cookie dough balls. Let the rest sit in the fridge while you form the first half. Take one and flatten the cookie dough.
Place 5 mini marshmallows in the center, and enclose them with the cookie dough. Roll the cookie dough between your palms into a ball. Coat with the granulated sugar and place it on a prepped baking sheet. Repeat this process for the rest of the cookie dough. Make sure the cookies are at least 2 inches apart.
Place the first tray into the fridge while you form the second half of the cookie dough. Alternatively, you can bake the first tray while you form the second half.
Bake for 10-12 minutes until the edges are slightly brown.
Once done, take the baking sheets out of the oven and tap them a few times on the counter. This helps the cookies get that crackly effect.
Cool for 10 minutes on the baking sheet before transferring them to a cooling rack to cool completely.