Heat a large pot on medium-low heat. Once hot, add the butter and let it melt. Add the flour and whisk into a roux, until the mixture is fragrant and slightly golden. Slowly pour in the heavy cream, milk and stock continuously stirring until thickened. Add in the potatoes. Reduce the heat to low and gradually stir in the cheese, making sure it doesn’t stick to the bottom. Simmer for about 15 minutes, stirring often. If the soup is too thick, add a bit more chicken stock. Stir in 2 slices of crumbled bacon and half of the green onions. Season with salt and pepper if needed.