½ bunch fresh basil, leaves picked
½ lemon, zest only
1 white onion, sliced
600ml/20fl oz fish or chicken stock
250g/9oz dried green lentils
salt and freshly ground black pepper
2 tsp herbes de Provence (see recipe tips)
1 tbsp olive oil
1 tsp smoked paprika
1 tbsp tomato purée
100²µ/3½´Ç³ú mascarpone
4 skinless, boneless haddock fillets (about 150–160g/5½–5¾oz each)
250ml/9fl oz tomato juice