Beat in egg yolk until well combined. In a separate bowl, whisk well all-purpose flour and earl grey tea. Gradually add the dry ingredients to the wet ingredients and mix until well combined with a silicon spatula.
Preheat the oven to 320°F (160°C). Remove the dough from the refrigerator. Spread granulated sugar on a piece of parchment paper and roll the dough over the sugar to coat evenly. Slice the dough into thin rounds, about 1/4 inch thick.