Make the tangzhong. In a small saucepan, whisk together the Water (1/4 cup), Milk (1/4 cup) and All-Purpose Flour (3 tablespoon). Whisk until no lumps remain.
Heat this mixture over medium low heat, stirring constantly. The mixture will thicken and streaks from your whisk will appear, this usually takes about 3-5 minutes. Remove from the heat. Transfer the mixture from the saucepan to a clean bowl - let cool to room temperature.
Make the dough. Whisk together the Bread Flour (270 gram), Granulated Sugar (100 gram), Matcha Powder (3 teaspoon), Instant Dry Yeast (1 1/4 teaspoon), Fine Salt (1 teaspoon), and Non-Fat Dry Milk Powder (1 teaspoon) in the bowl of your stand mixer.
In a small bowl, whisk together the Whole Milk (70 gram), Vanilla Extract (1 teaspoon), whisked Egg (1) and the cooled tangzhong.
Add the liquid ingredients to the dry ingredients. With the dough hook, knead blend for a few minutes until just combined.
Add the Unsalted Butter (2 tablespoon) and knead the dough for about 7-10 more minutes. It will feel elastic and slightly sticky.
Knead the dough into a ball shape and place into a greased bowl. Cover and place in a warm place to rise for 1 1/2 hours.
Make the turtles. After dough is done rising, weigh your dough. Divide it into 8 equally sized pieces. Reserve 2 of the pieces for the heads and feet of the turtles.
Flatten each piece of dough into about a 4-5 inch circle. Add White Chocolate (90 gram) to the flattened dough, pressing the chocolate into the dough.
Fold the dough up and around the white chocolate, pressing the dough together to ensure it is well sealed.
Flip over the dough so the sealed side is facing down - repeat with the other 5 pieces of dough and the turtle bodies are done.
Place the turtle bodies on a parchment lined baking sheet, leaving 2 inches in between each turtle.
Take 1 of the reserved balls of dough and divide it into 6 equally sized pieces.
Roll each piece into a sphere and gently pinch one end of the sphere, slip the pinched end under the turtle body and press the body down at their meeting point, repeat until all of the bodies have heads.
Take the other reserved ball of dough and divide it into 6 equally sized pieces (about 12g). Divide each of these pieces into 4 small pieces (about 3g). You should be left with 4 small balls of dough per turtle for the feet (24 total small pieces).
Shape each of the 4 small balls of dough into an oval, pinching one end of each oval. Slip the pinched ends under the turtle body placing them where the turtle's feet need to be.
Once all turtles have heads and feet, make the eyes by taking 2 Black Sesame Seeds (12). Place them onto each head, gently pressing them into the dough with a toothpick.
Cover the completed turtle rolls with plastic wrap and put in a warm place to rise for about 30 minutes.
While the turtles are rising make the dutch crunch.
Whisk together the Active Dry Yeast (1 1/2 teaspoon), Water (1/4 cup), Granulated Sugar (1 tablespoon), Vegetable Oil (1 1/2 teaspoon), Salt (1/2 teaspoon), Rice Flour (1/3 cup) and Unsweetened Cocoa Powder (1 tablespoon). Whisk until smooth.
Cover with plastic and leave to rise while the turtles are rising.
When turtles are done rising, preheat oven to 350 degrees F (180 degrees C).
Stir the dutch crunch topping until smooth and then coat the top of each turtle body with the dutch crunch topping, spreading it evenly with a spoon until all of the topping is used up.
Sprinkle the dutch crunch coating with Granulated Sugar (to taste) and then bake the rolls for 20 minutes.
Remove from oven and place turtles on a rack to cool for about 10-15 minutes
Enjoy turtles while still warm from the oven - this is when they are at their best. Serve and enjoy!