Date and walnut ricciarelli

1. Preheat the oven to 170˚C, gas mark 3. Line 2 baking sheets with baking parchment. In a food processor, whizz the walnuts and orange zest to a fine crumb. Put in a mixing bowl and stir in the ground almonds and caster sugar. Put the egg whites and 25g icing sugar in another bowl and whisk to stiff peaks. Tip over the walnut and almond mixture, add the orange blossom water, vanilla extract and dates, then fold together until evenly combined.

2. Put 50g icing sugar on a plate and drop heaped tablespoons of the mixture onto it. Roll in the sugar, then shape into balls in your hands. Arrange, well-spaced, on the baking sheets, and press down to discs about 1cm thick. Sift the remaining icing sugar generously over the top, so they look completely white. Bake for 15-17 minutes, until the surface cracks. Cool for 5 minutes, then carefully transfer to a wire rack to cool completely.