Directions

1. Grind your peppercorns until fine using a pestle and mortar.
2. Use a stand mixer or electric whisk to beat together the butter, sugar and ground peppercorns for 3–5 minutes on medium-high speed until pale and fluffy. Stop and scrape down the sides of the bowl every so often. Reduce the mixer speed to low and add the flour and ground ginger, followed by the crystallized ginger. Beat briefly until just combined – you don’t want to overmix here as the shortbread will come out tough.
3. Turn the dough out onto a clean work surface and divide in half. Roll each half into a thick sausage, wrap in plastic wrap and chill in the refrigerator for at least 2 hours or until completely firm.
4. Preheat the oven to 350°F (180°C/160°C fan/gas mark 4) and line two baking sheets with baking paper.
5. Pour the granulated sugar into a large, shallow dish or onto a piece of baking paper. Unwrap each log of dough and brush the outside with the egg white, then roll each log in the sugar to coat. Use a sharp knife to slice the dough into rounds, about ½in (1cm) thick. Arrange them on the baking sheets, spacing them (2.5cm) apart. You may need to bake them in batches.
6. Bake the cookies for 14–18 minutes until the edges just start to brown. Let them cool completely before eating.