Preheat the oven to 350 degrees F. Line a rimmed baking sheet with parchment paper so that the parchment goes up the sides of the sheet by an extra 2 inches. Spray lightly with nonstick cooking spray.
In a medium bowl, sift together the flour, green tea powder, baking soda and salt and set aside.
In a large bowl and using an electric mixer, cream together the butter and granulated sugar at medium speed. Add the milk, vanilla and beaten eggs and beat until the ingredients are well combined. Add the dry sifted ingredients and incorporate well. Stir in the dark chocolate chips and orange zest.
Pour the mixture into the prepared baking sheet and use an off-set spatula to spread the "crownie" out into a 1/2-inch-thick rectangle, about 8 inches by 11 inches. Bake for 15 to 20 minutes. As it comes out of the oven, let it cool slightly for a few minutes.
Take a 2 1/2-inch round ridged cookie cutter and cut out rings from the "crownie." You can lay them out on a wire rack to cool further before serving, but I like to eat them while they are still warm. The "crownie" should be cookie-like on the outside but with a soft not overly dense middle--lighter than a brownie and crumbly on the outer edges like a good cookie. Dust with some confectioners' sugar if using.
You can serve the "crownies" with a cold glass of milk, chilled eggnog or a cup of tea. Or, have them as a dessert with vanilla ice cream. Enjoy.