Top and tail the leeks and remove the outer skin. Separate the white and green parts retaining all the white and only the lighter inner stem of the green leaves. Slice thinly before rinsing under running water. Continue until the required weight of leeks has been harvested

Choose relatively small onions. Half the onion then cut the halves into quarters. Slice the quarters thinly.

Slice the celery lengthwise into narrow stalks then chop into small pieces.

Microwave the vegetables (other than the celery) in turn for 3 minutes each starting with the onion and whilst doing so put a large pan on the heat and add the stock (hot). Add the garlic powder and the bouquet garni. Add the vegetables as they finish microwaving. The potato will be second and the leek last (add some stock with the leek whilst microwaving).

As the pan comes to the boil after each addition turn down to a simmer. After the leeks (and their stock) are added set to simmer for 15 minutes.

Whilst simmering put the celery in a microwaveable container and add a ladle of the vegetable / stock combination well mixed. Microwave for 6 minutes. Transfer to the beaker of a hand blender and reduce to a paste before adding to the pan and mixing.

After the 15 minutes simmering time remove the bouquet garni. Serve in warmed bowls.

Add further seasoning to taste after serving.