Preheat the oven to 190°C. Prepare 8 squares of aluminium foil large enough to wrap 2 heads each of the garlic. Slice the top 3cm from each garlic head and place 2 heads in the centre of each foil square. Season with salt and freshly ground white pepper and drizzle with olive oil. Carefully fold the foil to enclose the garlic heads, place in a roasting pan and roast for 20 minutes or until the garlic is soft when squeezed. Meanwhile, in a saucepan over medium heat melt the butter, add the onion and leek and cook until soft. Add the potatoes and sauté for 3 minutes. Add the Simon Gault Home Cuisine vegetable stock, bring to a simmer and cook until the potatoes are fork tender (about 20 minutes). Remove the garlic from the oven when cooked and set aside to cool. Carefully squeeze the garlic from the skins into a bowl, being sure to remove any stray pieces of skin that fall in. Add the garlic and milk to the saucepan and stir to combine. Transfer the soup to a blender and purée until smooth. Season with salt and pepper to taste. Pour into 6 bowls, garnish with a swirl of cream and serve with grilled bread. I used kumara bread.