Place the potatoes and water into a large saucepan. Bring to a boil and simmer covered for 20 minutes or until the potatoes are tender. Drain the potatoes, reserving the liquid.
With a potato masher or food mill, puree the potatoes and add to the liquid.
Heat the 2 tablespoons of butter and oil in a skillet and saute the leeks and zucchini for a few minutes. With a slotted spoon, remove the vegetables and add to the soup.
Add the bouillion cubes to the soup and simmer for 20 minutes.
Meanwhile to the same skillet, saute the chicken strips for 5 minutes in the same fat used to saute the vegetables until just a smidgen before they are cooked through (if necessary add a couple of tablespoons more of butte prior to sauteing the chicken, to prevent it from sticking to the pan). Remove the skillet from the heat and add the ham. Mix well and set aside until ready to use.
When the soup is cooked, add the cream or half and half, chicken and the ham. Season with salt and pepper, and nutmeg. Heat thoroughly, being careful not to let it come to a boil so as to prevent cream from curdeling. Add the lemon juice to taste, being careful not to over-do so as not to overpower the soup with too much acidity. Garnish with chives or scallions. Serve hot.