Peel the sweet potatoes if desired and chop them into roughly 2-inch chunks for even cooking.
Dice the yellow onion and smash or mince the garlic cloves to release their fragrant aroma.
Add the sweet potato chunks, diced onion, and smashed garlic into your slow cooker.
Pour in the vegetable broth and coconut milk, then sprinkle in the cumin and cinnamon for warm, inviting spices.
Stir everything gently to combine, then cover and cook on low for about 6 hours, until the sweet potatoes are very tender and fragrant.
Once cooked, carefully use an immersion blender to puree the soup directly in the slow cooker until smooth and velvety, or transfer in batches to a blender, blending carefully with vented lid.
Check the consistency and season with salt and pepper, adjusting to taste. If the soup is too thick, stir in a splash of warm broth until it reaches your desired creaminess.
Serve hot in bowls, garnished with a drizzle of coconut milk or herbs if desired, and enjoy the rich, sweet aroma and smooth texture.
