Add peeled and cubed sweet potatoes, sliced carrots, diced onion, and minced garlic into the crockpot.
Pour vegetable broth over the vegetables until they are just covered, then drizzle with olive oil.
Season with a pinch of sea salt and black pepper, then give everything a quick stir to combine.
Cover the crockpot and set it to low. Let it cook for about 6 hours until the vegetables are tender and starting to break down.
Once cooked, carefully transfer the mixture to a blender or use an immersion blender directly in the crockpot to puree until smooth and velvety.
Return the soup to the crockpot or a pot, taste, and adjust seasoning as needed with more salt or pepper.
Serve hot, garnished with a drizzle of olive oil or a sprinkle of herbs if desired.