Olive oil should be heated over medium heat in a Dutch oven or soup pot. Cook the sausage for 5-6 minutes, stirring constantly. Using a slotted spoon, take out the sausage.

During the next 2 minutes, throw in some chopped garlic, onions, carrots, and celery.

Put the potatoes and chicken stock in a saucepan. Crank up the heat until the mixture boils, and then turn it down. Cook the potatoes, covered, for about 15 minutes, or until they are fork-tender.

Put in the cooked sausage, milk, cheddar cheese, parmesan cheese, salt, and pepper. To melt the cheese, stir and continue cooking over low heat for another 5-10 minutes.

Before serving, mix with some chopped parsley.