Line several rimmed baking sheets with parchment paper.
In a medium bowl, combine flour and loose tea, whisking well.
In a large bowl, combine butter, confectioners’ sugar, and vanilla extract. Beat with a mixer, beginning at low speed and gradually increasing to high, until light and creamy. Add flour mixture, beating until incorporated.
Divide dough into 2 portions, flat- ten each portion into a disk, and wrap securely in plastic wrap. Refrigerate until dough is hard but still soft enough to roll out, approximately 1 hour.
On a lightly floured surface, roll each portion of dough to a ¼-inch thickness. Using a 1½-inch fluted round cutter, cut as many shapes from dough as possible, rerolling scraps as necessary. (Gather scraps into a ball, wrap securely in plastic wrap, and refrigerate to harden again before rerolling.)
Place cookies 2 inches apart on prepared baking sheets. Freeze for 20 minutes to prevent cookies from spreading as they bake.
Bake cookies until set, 9 to 10 minutes. Transfer cookies to a wire rack, and let cool completely.
Place Pink Buttercream in a pastry bag fitted with a medium open-star tip (Wilton #21). Pipe buttercream onto flat surface of half of cookies, outlining edges and then filling in centers. Top with remaining cookies, flat side down.
Place cookies in an airtight container, and refrigerate until needed.
Notes
*We cut open 11 tea bags of The Republic of Tea raspberry rose hibiscus tea to get 2 tablespoons loose tea. Make-Ahead Tip: Bake cookies up to a month in advance, and freeze (unfilled) in an airtight container until needed. Fill and assemble cookies just before serving.
Recipe by TeaTime Magazine at https://teatimemagazine.com/raspberry-rose-shortbread-sandwich-cookies-recipe/