t Five egg whites
t Pinch of salt
t 75g/3oz caster sugar
t 175g/6oz ground almonds
t Grated orange zest
t One tbsp orange liqueur (optional)
t 25g/ 1oz slivered almonds
t Preheat the oven to 190C (375F)
t Grease and line a 20cm/ 8in spring form cake tin.
t Whisk the egg whites with the salt until they stand in soft peaks.
t Whisking constantly, add the sugar a little at a time.
t Continue whisking until the mixture is firm, shiny and very thick.
t Fold in the ground almonds, orange zest and the liqueur with a metal spoon.
t Pour the mixture into the cake tin and sprinkle the slivered almonds over the top.
t Bake for 30 minutes or until skewer inserted into the centre comes out clean.
tAllow it to stand in the tin for 10 minutes, then loosen, turn out and leave to cool on a wire rack.