Heat the oven to 170C/fan 150C/gas 3 and roll spoonfuls of the mixture into 20 balls. Arrange the balls on the trays, spaced well apart – you may need to rinse your hands every so often as the mixture gets sticky, and press the balls together quite firmly so they don’t fall apart. Flatten each ball slightly using the back of a spoon or your fingers. Transfer to the oven and bake for 10-12 minutes, or until golden and firm. Leave to cool for 5 minutes on the trays, then transfer to a wire rack to cool completely.