1 1⁄2 lb. boneless, skinless cod filets, cut into 2″ chunks
1/2 tbsp. mustard seeds, lightly crushed
2 tbsp. salted butter
1 shallots, finely chopped
675g fresh (un-podded) or thawed frozen peas
Rock salt and freshly ground black pepper, to taste
80ml half milk, half Cream
1 tbsp. Rapeseed oil
Roughly chopped dill, to garnish
1/ Sprinkle cod evenly with mustard seeds and let marinate in the refrigerator for 2 hours.
2/ Meanwhile, heat butter in a frying pan over medium heat. Add shallots; cook until soft, about 5 minutes. Add peas, 240ml water, and salt and pepper, and cover partially with lid; cook until sauce is reduced, about 10 minutes. Set sauce aside and keep warm.
3/ Puree 75g shelled peas, milk and cream mixture, and salt and pepper in a food processor; transfer to a 4pint saucepan and keep warm over low heat.
4/ Heat oil in a frying pan over medium-high heat. Add cod; cook, turning once, until golden brown, about 4 minutes. Season with salt. Divide pea puree among 3 serving plates and top with cod; spoon over sauce and garnish with dill.