In a large saucepan, heat the oil and fry the bacon over a low heat until crisp. Remove ¼ and set aside for garnishing.
Add the sliced leek, thyme, and salt, and cook until soft, approx. 5 minutes.
Add the potatoes and chicken stock, bring up to a simmer, and cook for 20 minutes or until the potatoes are tender.
Add the cream and black pepper and adjust the seasonings to taste.
Meanwhile, preheat your grill. Arrange the bread slices on a tray and grill until lightly browned, then flip over and brown the other side.
Top with the provolone and cook until just melted and gooey.
To serve, ladle the chowder into bowls. Sprinkle with the remaining bacon, parmesan, and parsley and serve with the toasts alongside.