Preheat oven to 375°F (190°C) and line a muffin tin with paper liners or grease it lightly.
Prepare dry ingredients: In a large bowl, sift together flour, matcha powder, baking powder, baking soda, and salt. Mix well.
Prepare wet ingredients: In another bowl, whisk together sugar, melted butter, eggs, milk, and vanilla extract until smooth.
Combine wet and dry ingredients: Gradually add the wet mixture into the dry ingredients, stirring gently until just combined. Do not overmix.
Prepare blueberries: If using frozen blueberries, coat them lightly in 1 tablespoon of flour to prevent them from sinking.
Fold in blueberries: Gently fold the blueberries into the batter using a spatula.
Fill muffin cups: Spoon the batter evenly into the muffin tin, filling each about ¾ full.
Bake: Place in the oven and bake for 18-22 minutes, or until a toothpick inserted in the center comes out clean.
Cool: Let muffins cool in the pan for 5 minutes, then transfer them to a wire rack to cool completely.