Preheat an oven to 400°F. Take each of the sweet potatoes and stab them several times with a fork. Wrap each of the sweet potatoes in aluminum foil and then place on a baking sheet. Roast the sweet potatoes for 60 minutes.
At about 40 minutes of the potatoes roasting, add the cauliflower to the baking sheet and allow to roast for the remaining 20 minutes. Once the time has passed, set the cauliflower to the side. Check if the sweet potatoes are done by piercing one with a knife. If it inserts easily, it is ready. Otherwise, roast until it is soft enough.
Heat a pot over medium heat and coat with canola oil. Add the fennel bulb, onion, red onion, and garlic and cook until they are soft, about 8 to 15 minutes. Sprinkle the softened vegetables with the thyme and sage. Add the roasted vegetables and vegetable broth and bring to a slight boil. Lower heat and simmer for 10 minutes.
Turn off the heat and transfer the contents in the pot into a blender and blend until smooth. Return to the pot and turn on the heat to low. Add the monster extract and lime juice. Heat until the soup has warmed all the way through. Season with salt and pepper to your liking. Serve in a bowl topped with the garnishes.
