Make soup: Preheat oven to 425℉. Place carrots, onion, garlic, and ginger on baking tray lined with parchment. Sprinkle with salt and pepper. Drizzle with olive oil, and toss to coat evenly. Roast for 25-35 min. until carrots are soft when pierced with fork. Turn oven down to 400℉ in preparation for shallots. Let roasted veggies cool 5 min.
While veggies are roasting, make Roasted Shallots: Add shallots to a parchment lined baking tray. Sprinkle with buckwheat flour, salt, pepper, and garlic powder. Drizzle with olive oil and toss to coat evenly in oil and flour. Spread into single layer. Once veggies are done and oven is cooled to 400℉, roast shallots for 8-12 min until browned but not burnt.
Add roasted veggies to a blender with 2 cups bone broth (remaining broth will be added later) and nut milk. Set aside.
Add remaining 2 cups bone broth to 4.5 qt pot and bring to a simmer. Whisk in miso. Add carrot puree mixture and whisk to blend. Cover, bring back to simmer, and cook 10 more minutes, removing cover after 5. Stir frequently. You may need to turn heat down to keep at a simmer.
Serve topped with roasted shallots, minced herbs, and sesame seeds.