Preheat oven to 400. Chop/slice veggies except for the kale, and drizzle well with olive oil, salt and pepper and roast until tender. (You can add other veggies too)In a large pot, combine stock and roasted veggies and thyme and simmer until veggies become very soft. This is a blended soup- you can choose to add the chopped kale to the stock and blend with the veggies or add after blending for different texture option. Use an immersion blender to puree the soup. You will find that the longer the veggies can cook, the easier they blend. You may find strings of the leeks that you can remove or simply let keep cooking and they will break down on their own. I have added ham and various flavors of sausages along with cheese from swiss to asiago. You can switch out veggies and add more as well. Roasting the vegetables first gives the soup a richer flavor.