1Heat the oil and butter over medium heat in a large pot.
2Add the onion and garlic and simmer until the onion is.
3Stir in potatoes, water of bouillon, milk, salt and pepper and bring to a boil.
4Reduce heat to low and simmer until the potatoes fall apart, 30-45 minutes.
5Mash the potatoes a bit with the back of a spoon.
6Remove the soup from the heat and stir in the cheese.
7Season to taste and serve immediately.