Line a large baking sheet with parchment paper and grease with cooking spray or butter.
In a large bowl, mix together the flour, matcha powder, sugar, baking powder and salt until all dry ingredients are evenly incorporated.
Cut the butter in pieces half-inch wide and add to the same bowl. Use an electric mixer to beat at medium speed for about 3 minutes. The resulting mixture should almost look like sand.
Add the eggs and vanilla and mix until a dough forms.
On a floured surface, shape the dough into a flat disk in any size. Wrap the disk using plastic wrap and place it in the fridge. Let chill for 30 minutes.
Preheat the oven to 350 F.
After 30 minutes, remove the disk from the fridge. Divide the dough in half and shape each piece into an oval. Using a rolling pin (or your hands), lengthen each oval piece to form two logs that are around 5 inches wide and 12 inches long.
Place logs on the prepared baking sheet. Bake for 20 to 25 minutes.
When done, remove the tray from the oven and let the logs cool for 20 minutes.
Lower the oven temperature to 300 degrees F.
After the logs have cooled, place them on a cutting board. Using a knife, slice them horizontally into pieces that are about an inch in width.
Place the biscotti pieces back onto the baking sheet with either one of the cut-sides facing down onto the sheet. Bake for 10 minutes.
Remove the baking sheet from the oven briefly to flip the biscotti pieces using a pair of tongs so that the original cut-side is now facing up. Continue baking for another 10 minutes.
After removing the pieces from the oven, let cool for 30 minutes. Then, enjoy!