First of all you need your stock made from any bones, but in this instance I used a ham bone, water, white pepper an onion about 4 whole black peppercorns, small piece of celery leaf,(not too much required as this can overpower your soup as it is very strong) small carrot chopped in slices couple of bay leaves, dried thyme (I use a faggot of thyme and just rub in a litte from the bunch), sprinkling of dried cloves or about 2 to 3 full cloves studded into the onion, a few dried marigold flowers.
Basically I just simmer everything together until a nice flavourful stock is achieved. I then leave this to cool any fat that rises to the top of the stock on cooling (there will be a little) can be skimmed.
In a large oven tray [using older vegetables that you probably wouldn't use for a main meal] tidy them up removing any peels, dried out leaves until you get to the better part of the vegetable - its worth the effort. I use a mixture of seasonal vegetables - whatever is to hand really but in this case the veggies I used were sliced leek, potato, squash (there is no need to peel this just de-seed) small cherry tomatoes, a sprinkling of chilli powder, olive oil, onion and sometimes I add garlic as well. Cook in the oven about Gas mark 5 liberally sprinkled with Olive Oil and a sprinkling of sea salt auntil nicely caramelised without being burnt as this adds extra flavour and punch.
Using your stock add the vegetables to the pan and then use a stick blender (if you don't have just bung it in your food processor until nice and thick and then transfer the mixture from the food processor) to your stock and adjust the thickness of the soup with the stock until the desired thickness is achieved. Warm through adjust your seasoning and serve with home-made croutons or bread.