Instructions

• Preheat the oven to 350°F. Line an 8×8-inch baking pan with parchment paper, leaving an overhang on at least two opposite sides to use as handles.
• In a large mixing bowl or the bowl of a stand mixer fitted with the paddle attachment, beat the room-temperature butter and granulated sugar together on medium speed until light and fluffy, about 2–3 minutes.
• Add the egg, then add the 1/2 teaspoon pure vanilla extract and the 1/2 teaspoon kosher salt. Beat just until combined, stopping to scrape down the sides and bottom of the bowl as needed.
• In a small bowl, combine the 1 1/2 cups all-purpose flour and the 1 teaspoon finely ground Earl Grey tea (opened from the tea bag and finely ground). Add the flour–tea mixture to the butter mixture and mix on low speed until just incorporated. Do not overmix.
• Transfer the dough to the prepared pan. The dough will be sticky; lightly flour your fingertips or place a sheet of plastic wrap over the dough and use it to press the dough into an even layer in the bottom of the pan.
• Bake for 28–30 minutes, until the top is puffed and matte and the edges are just beginning to turn a very light golden brown. Remove the pan from the oven and set it on a wire rack to cool completely in the pan.
• Make the glaze while the shortbread cools: in a small bowl whisk together the 1/4 cup sifted powdered sugar and the 1 tablespoon blood orange juice until smooth. The glaze should be the consistency of honey — a drizzle should hold its shape for a few seconds before settling. If the glaze is too thin, add a little more sifted powdered sugar to thicken. If it is too thick, add more blood orange juice in 1/2-teaspoon increments until you reach the desired consistency.
• When the shortbread is completely cool, lift the entire block from the pan using the parchment overhang. Place it on a cutting board or leave on the parchment.
• Drizzle the glaze over the shortbread using a fork, whisk, or a squeeze bottle for more control. Allow the glaze to set briefly.
• Cut the shortbread into squares, then cut each square in half diagonally to make triangles. Store the cookies in an airtight container at room temperature for up to one week, or freeze for longer storage.