We don't need the EU! We don't need the rest of the world! We just need to bring back monastic farming: raise fish in fish ponds, rabbits in rabbit warrens (or back gardens), pigeons in dovecotes (for their eggs). Like the Anglo-Saxons, we can install eel and fish traps/weirs in rivers.
Let's eat the invasive American crayfish, with a side order of Japanese knotweed (fry young tender shoots in butter).
Let's use native species, like chestnuts and seakale.
Use peeled chestnuts (make sure they're not imported), or forage your own. To peel, make a slit in the sides of the nuts, boil for 15 mins. While still warm, remove shells and skins.
salt and pepper
Fry the chopped onion in the butter, add stock, chestnuts and other ingredients and simmer. Mash the chestnuts with a potato masher. Add cream if liked.
Puréed chestnuts mixed with sugar, butter and dark chocolate make a pudding called Turinese. Top with whipped cream.
SEA KALE IN WHITE SAUCE
Sea kale, a relative of the cabbage with blueish leaves, grows on shingly beaches. Forage the leaves and boil until soft. Or take the root, plant it in your garden, and put a big flower pot over it to force it like rhubarb – the leaves will be paler, softer and sweeter.
A piece of butter the size of a walnut, flour, milk.
Melt the butter in a saucepan over a low heat and add a tablespoon of flour. Mix until the flour swells, then add a cupful of milk. Mix again until smooth. Keep adding milk in small quantities, and stirring – you can remove lumps with a hand whisk. Bring to the boil, then reduce to a simmer and let cook for 20 minutes, stirring occasionally. Add salt and pepper. Stir in grated cheese to make a cheese sauce.
Mrs Beeton would line a vegetable dish with buttered toast, put a layer of kale on top, then pour over the sauce. All this would work with ordinary kale - boil until soft.