Rhubarb & white chocolate cookies

For the rhubarb, cut the stalks into 1.5cm pieces and mix with the caster sugar in a bowl; let stand for 30 minutes to macerate. Meanwhile, roughly chop the white chocolate and crystallised ginger into small pieces.

For the dough, use an electric hand mixer to cream together the butter and both sugars in a bowl until fluffy (4-5 minutes). Add the egg and mix until combined. In a separate bowl, mix together the flour, baking powder, bicarbonate of soda and salt. Gradually mix the dry ingredients into the wet until combined.

Fold 100g of the macerated rhubarb into the dough with most of the chopped chocolate (reserving 12 pieces) and crystallised ginger. Line 2 baking trays with baking parchment. Scoop the dough into balls (each about 70g and 5 cm wide) and put on the prepared trays. Press 1 or 2 pieces of reserved rhubarb and white chocolate onto the top of each cookie. Chill for at least 2 hours (or overnight). Some syrup may have leaked from the cookie balls; just wipe them with a clean kitchen towel.

Preheat the oven to 180ºC, gas mark 4. Bake for 15-17 minutes, until the edges are golden and the centres still soft, swapping the trays halfway through. If the cookies warp as they bake, you can always nudge them back into shape with a spoon while they are still warm. Cool on the trays for 5 minutes before transferring to a wire rack to cool completely.