Ruby grapefruit and Campari sorbet

Method

1. Slice all the skin and pith from the grapefruit and cut the fruit into large chunks. Put in a food processor or blender and whizz to a fine pulp. Pour into a sieve set over a large bowl and let the juice run through, then squeeze the pulp to extract all the juice (about 500ml).
2. Mix 200ml of the juice with the sugar in a pan and heat gently until the sugar just melts. Strain the orange juice into the bowl with the remaining grapefruit juice, add the Campari and the warmed grapefruit juice, then stir well. Leave to cool completely, then churn the syrup in an ice cream machine until softly frozen. Put in the freezer to firm up.
3. Heat the oven to 170°C/fan150°C/gas 3½. For the shortbread, heat a frying pan with a small splash of oil and add the almonds and a large pinch of salt. Toss for a few minutes until the nuts are pale golden, then tip onto kitchen paper to cool. In a large bowl, mix the butter and sugar, then stir through the flours and another small pinch of salt.
4. Work the mixture together with your hands until it forms small chunks, then knead through the almonds until the dough comes together. Press into a 20cm square baking tin lined with baking paper. Smooth the top with a spatula, chill for 10 minutes, then sprinkle a little extra caster sugar on top.
5. Bake for 20 minutes, then remove from the oven and score halfway through with a sharp knife into 12 bars. Return to the oven for another 20 minutes or until a pale sandy colour. When ready, remove from the oven, leave the shortbread in the tin to cool for 20 minutes, then cut into bars. Cool completely, then store in an airtight container until needed.
6. Serve scoops of the sorbet in frozen bowls with the shortbread.