Put the olive oil and onion in a large pot over medium high heat and saute for 5 minutes. Add the pancetta and cook for another few minutes, then remove from pan and set aside.

Add the butter to the pot, and when melted, add the flour and mix well. Cook for about 4 minutes over medium high heat, then slowly begin adding the milk, a little at a time. If you add too much milk at first, the white sauce can turn lumpy. Continue to add milk gradually, adding a little more each time, mixing until it is completely absorbed before adding more, until it has all been added. If you find you have lumps, just use a stick blender to fix the problem-I won’t tell! ;)

Next, add the water or stock, and liquid from the clams. Taste for salt, adding more if needed, then put the pancetta and onion, and potatoes into the soup. Simmer over low heat, stirring often and scraping the bottom to make sure it doesn’t stick. When the potatoes are ready, add the clams and parsley and cook for 3 minutes or so.

Taste for salt again, and add some freshly ground pepper and remove from heat. When ready to serve, cut the top off of the sourdough boules, and remove some of the inside to form a bowl, and reheat in a hot oven for about 5 minutes, to make the crust crispy. Ladle hot chowder into the bread bowl. Garnish with more parsley if desired.