In a large mixing bowl, cream together the butter and sugar until light and fluffy, about 3-4 minutes. Blend in tea leaves, vanilla extract, and salt.

Gradually mix in all-purpose flour until a smooth dough forms.

Shape the dough into a log, wrap in plastic wrap, and refrigerate for about 30 minutes.

Preheat your oven to 300°F (150°C). Slice the chilled dough into 1/4-inch thick rounds and place on a lined baking sheet.

Bake for 15-20 minutes or until edges are lightly golden. Cool on baking sheet for 5 minutes before transferring to a wire rack.