Remove cauliflower florets from core, peel parsnips and remove tops. Liberally coat cauliflower, parsnips and garlic cloves with extra virgin olive oil and salt. Roast at 350F for 30-40 minutes until golden.
In a large stock pot, heat 2 tablespoons olive oil. Add leeks, season with salt and black pepper. Once leeks are translucent, add roasted vegetables, white wine, stock, and the next 6 ingredients. Bring to a simmer, about 20 minutes, to ensure roasted vegetables are softened. Remove bay leaves, set aside.
Using a hand blender, purée until smooth. Add half and half and purée again to ensure incorporated. Add bay leaves back to the pot and simmer for 15 minutes.
For the garnish:
In a medium sauce pan, heat 2 cups of vegetable oil. Once hot, add a small amount of leeks at a time, frying until crispy. Use caution, oil will splatter as leeks are added.