In a large mixing bowl or the bowl of a stand mixer, whip the butter on high speed until soft and creamy.

Add the granulated sugar and lemon zest and mix on high speed until well-combined.

In a separate bowl, stir together flour, Earl Grey tea, and salt.

Add dry ingredients to the butter and sugar mixture, and mix on low until it resembles coarse breadcrumbs.

Use your hands to bring the mixture together, kneading gently until a loose, crumbly dough forms.

Shape into a log, approximately 7 inches long and about 1 3/4 inches in diameter.

Wrap log in clingfilm/plastic wrap and chill in the refrigerator, at least 1 hour or until firm.

While dough chills, preheat oven to 180° C / 355° F. Line a half-sheet rimmed baking tray with parchment or a silicone mat, and set aside until ready to use.

Unwrap the log and trim the ends. With a sharp chef’s knife, slice into slices, each about 1/4 inch thick. You should have approximately 18-20 slices.

Transfer to prepared tray.

Bake in preheated oven until shortbread is lightly golden around the edges, about 13-15 minutes.

Remove from oven and allow to cool on the tray.

Once cool, melt the white chocolate in a microwave-safe bowl, or over a bain marie or double boiler.

Transfer to a piping bag.

Pipe zigzags over the cookies.

Allow cookies to sit, uncovered, at room temperature until the chocolate sets.

Store Earl Grey shortbread cookies in an airtight container at room temperature for up to five days.