Trim the dark green parts of the leek. Peel off and discard the uppermost layer. Slice the leek in half and rinse away any dirt. Chop into thin slices.
Place all of your fresh sprigs and leaves into a cheesecloth and tie together. Or, an even better idea, use a bouquet garni (an already prepared combination of dried soup herbs in a little pouch or tied together with a kitchen string).
Melt the butter in a large pan (this makes a lot of soup). Stir in the leeks and cook until soft and “dark golden brown”, 10-15 minutes.
Stir in the garlic for the last 3 minutes.
Add the vegetable stock and the herbs. Season with salt and pepper. Bring to a boil and then reduce heat and simmer 5 minutes.
Add potatoes and simmer until the potatoes are tender, requiring up to 45 minutes.
Taste and adjust seasoning.
Decorate with parsley and serve with a small amount of cream.