Place the butter and flour in the bowl of an electric mixer, mix with paddle attachment the mixture resembles small peas. Add powdered sugar, orange zest, baking powder and salt, mix to combine. Add egg yolks and mix jut enough to make a smooth dough. Do not over mix the dough or it will become tough. Remove the dough from the bowl. If your butter was very cold, you will be able to roll the dough immediately. If not, place it in the refrigerator.
Preheat the oven to 350 degrees F. If necessary, remove the dough from the refrigerator. The dough will be hard when it comes out of the refrigerator and you will need to give it a few quick raps with a rolling pin to make it easier to roll. Lightly flour the dough and roll out into a 5 by 10-inch rectangle about 1/4-inch thick. Cut 1-inch square cookies and place them on a parchment paper-covered baking sheet about 1/2-inch apart. Bake until lightly browned, about 15 minutes and cool on a wire rack. Arrange the cookies on a silicone mat covered baking sheet. Cut the stems from the edible flowers and place 1 flower on top of each cookie.
Place the sugar, corn syrup and water in a large saucepan and cook to 320 degrees F. Pour a small amount of cooked sugar on the short side of a silicone baking mat placed over marble or granite. Use an offset spatula to spread the sugar evenly over the entire mat until it is about 1/16-inch thick. The spread sugar will cool very quickly but you want to use it while it is still warm.
Overturn the sugar layer onto the cookies and remove the silicone mat from the thin sugar sheet. Use a mini-torch or heat gun and melt the sugar until it melds into the flower and coats the cookie. Use the heat of the torch to "cut" the cookies from the sugar. Move the finished cookie to a platter.
Recipe credit Jacques Torres Chocolate, MrChocolate