Preparation

Active Time: 10 minutesInactive Time: 30 minutes, plus up to 25 minutes for bakingPut the tea and granulated sugar into the work bowl fitted with the chopping blade. Process on High for 30 to 40 seconds, or until finely ground. Add the butter, confectioners’ sugar and vanilla. Pulse 2 to 3 times and then process on High until creamy, about 1 minute.Scrape down sides and add the flour and salt. Pulse to combine, using about 10 long pulses. Remove dough and transfer to a lightly floured piece of parchment or wax paper. Form the dough into a log, about 12 inches in length and 1½ inches in diameter. Wrap well in the parchment or wax paper, dusting off excess flour. Chill in the freezer for 30 minutes.*While dough is chilling, preheat oven to 350°F with the racks in the lower and upper middle positions.Once dough has chilled, remove from freezer and allow to sit for 5 minutes. Put the demerara sugar into a shallow pan or plate and roll the dough so the sugar coats the surface of the long sides.Slice the dough into ¼-inch slices and place onto a parchment-lined baking sheet, leaving about ½ inch between cookies. (Chill any dough in the refrigerator that is not being baked right away.)Bake in the preheated oven until just golden at the edges, about 8 to 12 minutes.