Melt butter in a dutch oven or stock pot and add leeks and garlic. Cook on medium heat, 5 to 7 minutes stirring to prevent browning.
Add the wine, stock, potatoes, bay leaf and seasonings and bring to a boil. Cook 20 minutes to soften.
While the soup cooks, lightly coat the leek slivers with olive oil and fry in a skillet on medium heat until nicely browned. Remove to a paper towel lined plate.
Once the potatoes are nicely softened, remove the bay leaf from the pot and use a potato masher to coarsely mash the potatoes to thicken the soup.
Stir in the cream and let it warm up a couple minutes.
Serve hot and garnish with the fried leeks.