Preheat the oven to 380F.
Wash beets and carrots under cold water and cut off the top and bottom. Toss with olive oil, salt & pepper. Place in a baking dish, add garlic cloves and peeled potatoes, cover with tinfoil and bake for 40 minutes.
In a medium pot, heat the olive oil with crushed cumin and coriander seeds and bay leaves. Add flour and cook for 2 minutes. Stir in baked vegatables and cook for 1 minute.
Stir in warm stock, and season with salt and pepper. Bring to a boil; cover, and simmer until the beets are tender, about 15 minutes.
With an immersion or regular blender, puree soup, adding warm water as needed to reach desired consistency. Garnish with fried beet leaves and creme fraiche.