Can you tell me what plant this is please

Thanks CM. I was asking because had a meal at a 'master chef' type restaurant and the main course was sprinkled with Allium cultivar flowers and the leaves and flowers of this, as well as what looked decidedly like very young growth plantain which had been cooked (still have not worked out what that could be). Daughter's meal came bedecked with sea beet and chickweed with flowers. Restaurant Mitchlin starred for it's local products - I had Guinea Fowl? lol.