150²µ/5½´Ç³ú blueberries
½ lemon, finely grated zest
1 tsp cornflour, mixed with 1 tsp water
1 vanilla pod, split and seeds scraped
3 reduced-calorie rich tea biscuits (about 25g/1oz)
½ ready-made individual meringue (18g/½oz), lightly crushed
450g/1lb lemon fat-free Greek-style yoghurt