For the Dough

1. Add the softened butter and icing sugar to a mixing bowl. Press the icing sugar into the butter using a spatula until a rough mixture forms.
2. Beat the mixture using a handheld mixer at medium speed until pale and fluffy.
3. Add the double cream and vanilla extract, then give it a quick mix.
4. Place a sieve on top of the mixing bowl and sift in the cake flour, cornflour, and salt. Gently mix until well combined.
5. Cut open two Earl Grey tea bags and stir the loose tea into the dough using a spatula, scraping down the sides and bottom of the bowl to ensure everything is evenly mixed.
6. Line your U-shaped cookie mould with a sheet of parchment paper, leaving some overhang on the sides.
7. Transfer the dough into the mould. Press it down firmly using your spatula or hands to ensure there are no air bubbles.
8. Fold the overhanging parchment paper tightly over the top of the dough.
9. Chill in the fridge for at least 1 hour, or until the dough is completely firm.

Bake the Cookies

1. Preheat your oven to 170°C fan.
2. Line a baking tray with baking paper.
3. Remove the firm dough from the fridge and gently lift it out of the U-shaped mould using the parchment paper.
4. Unwrap the dough and place it on a cutting board.
5. Using a sharp knife, slice the dough log into biscuits that are about 4mm thick.
6. Place the sliced biscuits onto the prepared baking tray, leaving about 2cm of space between each one.
7. Bake for 12 to 13 minutes, or until the edges turn golden.
8. Remove from the oven and let the biscuits cool on the baking tray for 5 minutes, as they will be very fragile while hot.
9. Transfer them gently to a wire rack to cool completely.