First, pre-heat your oven to 350F and line a baking sheet with a nonstick baking mat or piece of parchment paper.
In a large bowl, combine maple syrup, tahini and vanilla extract. Whisk to combine until completely smooth.
Next, sift in oat flour, almond flour and baking powder and use a spatula to mix until a dough forms. The dough should be workable and shapeable, so add oat flour by the tablespoon as needed (tahini texture will vary).
Set aside a third of the dough (this will be used to create the head, legs and turtle tail) and sift in matcha powder into the remaining dough. Use a spatula again to incorporate evenly.
Roll tablespoon sized scoops of your matcha dough into balls and pat down into cookie shapes on your baking mat. For each turtle cookie, roll small balls of plain dough to create a head, tail and arms/legs. Gently press together to bond. Finally, take a knife or the back of a fork to create a cross hatch pattern on the turtle shell. Use a chopstick or other tool to poke eyeballs into the head.
Finally, bake for 8-10 minutes, keeping in mind the cookies will firm up after baking. Let cool before enjoying.