When I was in Altamura, in Puglia, I worked with a family of bakers who all lived in the same big house. Each part of the family had its own living-room and kitchen. I went back home with them one day and four different families were cooking four different meals – it was very surreal. This pea soup was one of the dishes being made. And it's so simple – just four ingredients and 15 minutes simmering is all it takes. I've only ever made this soup with freshly podded peas, but frozen peas work well too. If I'm using fresh peas, what I like to do to make the soup even more tasty is to boil up the stock with the shells of the peas. You can do this while you're frying the onions. Then you can strain the stock onto your onions and peas when they're ready and fill the pan up again with water to boil your spaghetti while the soup simmers.
Pour a good lug of olive oil into a pan, add the onions and fry slowly for 10 minutes. Stir in the peas and chicken stock, bring to the boil and simmer for another 10 minutes or so. Bring some salted water to the boil and cook your spaghetti for half the time it says on the packet, then drain and add it to the pea soup to finish cooking. It's nice to tie up the sprigs of herbs and pop them into the soup to give it a lovely fragrance, removing them before serving. When the pasta is cooked, have a taste of the soup and season carefully with salt and pepper. Divide the soup between the bowls, drizzle over a little extra virgin olive oil and sprinkle with the parsley.