Add the flour and tea leaves to a food processorand process until the tea is ground and spotted throughout the flour. Add the salt, icing sugar, vanilla extract and butter and pulse until a dough forms. Remove from the food processor and roll into a log of roughly 6cm (2 ½ inches) in diameter and wrap in plastic wrap. Refrigerate for at least 30 minutes.
Preheat oven to 190 celsius (375 Fahrenheit) and line a baking tray with baking paper. Slice the dough into 24 cookies and bake for 12 minutes or until the edges begin to golden. Cool on the baking tray before transferring to a wire cooling rack to cool completely.