Authentic British fish and chip shop side: dried marrowfat peas steeped overnight, gently simmered until thick, soft, and mushy, finished with farmhouse butter, sea salt, and fresh garden mint.
Place dried marrowfat peas and bicarb tablet in a bowl, cover with boiling water, and steep overnight (approx. 12 hours) until plump and tender.
Drain and rinse steeped peas. Place in a saucepan with 750ml fresh water. Bring to a boil, skim foam, and simmer gently for 25-30 minutes until broken down and thick.
Stir in farmhouse butter, chopped mint, sugar, salt, and black pepper.
Beat with a wooden spoon to achieve the classic spoonable mushy pea consistency. Serve piping hot with fish and chips.