In a food processor pulse 1 ¼ cup of all purpose flour, 1 tablespoon granulated sugar and ¼ teaspoon salt together.
Cut ½ cup of cold butter into small pieces. While the food processor runs add the butter a few pieces at a time.
Add 2 tablespoon of cold water a little bit at a time until dough pulls together and starts to form a ball. (If the dough is still too dry after 2 tablespoon of water, add a little more water a tablespoon at a time until the right consistency is achieved).
Form the dough into a disk, wrap it with plastic wrap and chill it in the fridge for 1 hour or overnight.
When ready to make the galette, take dough out of the fridge and let sit for 30 minutes or so until it becomes a little softer.
On a floured surface, roll the dough out into a large circle, about 9 inches in diameter, about ¼ of an inch thick. Transfer the dough to a parchment paper lined baking sheet at this point.