Peel the potatoes and cut into cubes. Chop the onions into small pieces. Stew the potatoes and onions in butter for about 3 minutes. Pour in the vegetable stock and bring to the boil. Let simmer for about 15 minutes.
In the meantime, wash the wild garlic and remove the stalk. Cut the wild garlic into small pieces with a knife and add to the soup. Let it boil again for about 10 minutes, then puree everything well with the mixer. Chop the chilli pepper, toss briefly in the hot oil and pour over the soup.