Place butter and sugar in a large bowl. Beat on medium speed until fluffy. Add vanilla, flour, and salt. Beat on low speed until well combined. Stir in the tea and, if desired, orange zest. Divide dough into 4 equal pieces; press each into a flat disc. Wrap in plastic wrap and chill 30 min. (or up to 1 day).

Place rack in center of oven and preheat to 300°F. Line a baking sheet with parchment paper. Remove one disc from refrigerator and set aside to warm up 10-15 min. Unwrap and roll out the dough, on plastic wrap, with lightly floured rolling pin to about 1/4" thick. Dip cookie cutter into flour to keep it from sticking. Cut out and transfer dough with a spatula to prepared pan (I prefer a round, scalloped edge cutter). Bake until edges are golden brown, 15 -20 min. Transfer cookie sheet to cooling rack. When cool, peel off parchment paper. Cookies may be kept at room temperature in an airtight container up to 10 days.

Any unused dough may be frozen for up to 2 weeks.