In a large bowl or food processor whisk together the flour, sugar, salt, baking powder and zest.
If make by hand the make a well in the middle and add the egg and butter, start to combine with a fork, mix until almost combined. If using a food processor then add the egg and butter and pulse until almost combined.
If you find the dough too dry then add 1 -2 tablespoons of room temperature milk. But be sure to add it 1/2 tablespoon at a time.
Move the dough to a lightly floured flat surface and gently knead a few times to form a compact dough. Wrap it in plastic wrap and refrigerate for 15-20 minutes.
Pre-heat oven to 350F (180C). Line one or two baking sheets with parchment paper.
Remove the dough from the fridge, divide in 2 parts, one part wrap and place back in the fridge and the other part place on a lightly floured flat surface, lightly flour your rolling pin and roll very thin about 1/8 inch or thinner if you prefer. You could also use a pasta machine to roll out the dough.
Cut out strips, squares or shape long strips into a twist with a sharp knife, pasta roller or pizza roller. Place the strips on the prepared baking sheet, remove the other dough from the fridge and roll and cut. Bake for approximately 8-10 minutes or until golden.
Move the frappe to a wire rack to cool then dust with powdered sugar and serve. You can even dip them in melted chocolate, let the chocolate firm up before serving. Enjoy!
Notes
Yes you can, Italians like to add some grappa, marsala or even some rum. Or why not a bit of your favorite liqueur such as Grand Marnier or Limoncello? It should be added with the butter and egg. I think 2-3 tablespoons should be enough. When you add it you will have to increase a bit of flour also.The dough can also be made in a stand mixer, use the flat beaters and beat until just combined. Then move to a lightly floured flat surface to form the compact dough.Any leftover frappe should be kept in an airtight container and kept at room temperature. They will keep for up to 4 days.The dough can be made ahead of time, wrap it well in plastic wrap and refrigerate. It will keep for up to 2-3 days in the fridge.