Fry the onions, garlic, carrots and celery for about 5 mins until soft and without colouring
Add the sprouts and stir through and cook for a further 3-4 mins
Add the thyme and stir through
Add the stock, peas and potatoes and simmer for 20-25 mins until the potatoes are cooked through
Season and serve straight away if you want a chunky soup
For option two, just blitz the soup and stir in the cream
Feel free to use any unused fresh vegetable left over from you Sunday roast, use chicken stock instead of veg, rosemary instead of thyme and you could even add some leftover meat, if you have any that is!