Cook Onion & Garlic: Cook the garlic and onions with a pinch of salt in a couple of tablespoons of the vegetable stock for 5-6 minutes over medium heat. Stir often.
Add Spices: Stir in the curry powder and red pepper flakes and cook for 2-3 more minutes. Add another splash of broth if needed if the pan starts to dry out.
Add Liquid & Vegetables: Add the coconut milk, vegetable stock, sweet potato and cauliflower.
Cook Soup: Simmer lightly, uncovered, until the sweet potato is cooked through and easily pierced with a fork, approximately 15-20 minutes. Turn off the heat.
Blend: Carefully transfer the soup to a blender and processor until very smooth and creamy then pour back into the pot. Be sure to let the steam escape as you're blending. You can blend all of the soup for a cream soup or blend 1/2 of the soup to leave some chunky texture. Alternatively, use an immersion blender right in the pot and blend to your desired consistency.
Season: Stir in the lime juice, sugar and green peas and season with salt and pepper, to taste.
Serve: Serve right away topped with fresh cilantro and another spritz of lime juice, if desired.