200g/7oz blood orange juice
1 large red grapefruit, finely grated zest only
1 red grapefruit
1 orange
80g/3oz plain flour
70驳/2陆辞锄 polenta
1 tsp bicarbonate of soda
150驳/5陆辞锄 ground almonds
140g/5oz honey
160g/5戮oz clear honey
100驳/3陆辞锄 maple syrup
200g/7oz unsalted butter, softened, plus extra for greasing tins
2 large free-range eggs
250g/9oz mascarpone
200g/7oz red grapefruit juice