Earl Grey Rooibos Shortbread

Method

1. Open the 3 Earl Grey Rooibos bags by tearing the top edge and tipping the dry leaf into a small bowl. Use the back of a teaspoon to break any large leaf pieces into a finer confetti, but do not grind to powder; you want visible flecks in the finished shortbread.
2. Cream the 200g of softened unsalted butter, the 100g of golden caster sugar, the 50g of sieved icing sugar, the 1 teaspoon of vanilla bean paste and the 1/2 teaspoon of fine sea salt together in a large mixing bowl with an electric hand whisk for three to four minutes until the mixture is pale, fluffy and noticeably increased in volume.
3. Tip the broken tea leaf into the creamed butter mixture and beat with the electric whisk for thirty seconds to distribute the leaf evenly through the butter. The leaf should look like fine speckles, well dispersed.
4. Sift the 300g of plain flour and the 50g of cornflour together over the butter mixture in two batches, folding gently with a flexible spatula between each batch until just combined. Stop the moment the flour disappears; overworking the dough builds gluten and turns the shortbread tough.
5. Tip the dough onto a lightly floured surface, knead very briefly (six or seven gentle presses, no more) to bring the dough into a smooth lump, then shape into a flat rectangle about 2cm thick.
6. Wrap the rectangle tightly in cling film and chill in the fridge for at least thirty minutes, ideally an hour. The chill firms the dough for clean cutting and is not a step to skip.
7. Heat the oven to 160C fan or 180C conventional or Gas 4. Line a large baking tray with baking parchment.
8. Unwrap the chilled dough and either cut into 1cm thick fingers with a sharp knife, or roll out gently to 1cm thick and cut into rounds or wedges with a cutter. Arrange on the lined tray with a 2cm gap between each piece.
9. Sprinkle the 2 tablespoons of demerara sugar generously over the top of all the shortbread pieces, pressing the sugar lightly into the surface so it sticks during the bake.
10. Bake in the middle of the oven for twenty to twenty two minutes, until the edges are very pale gold and the tops are still pale. Shortbread should look slightly underdone rather than browned; it firms up as it cools.
11. Cool on the tray for five minutes (the shortbread is fragile when hot), then carefully transfer to a wire rack with a thin spatula and cool completely. Store in an airtight tin lined with greaseproof paper for up to one week.