Heat olive oil in a Dutch oven over medium high heat.
Once the oil is hot, add onions and crushed garlic to the Dutch oven. Saute about 3-4 minutes or until garlic is golden and onions are translucent.
Add in sweet potato cubes and spices, stir to coat then pour in vegetable broth.
Bring mixture to a boil then reduce heat to medium low and simmer (lid off) for about 30 minutes or until sweet potato cubes are very tender (stirring occasionally).
Reduce heat to low then emulsify the mixture using an immersion blender. Stir in yogurt, blend once more, season with salt and pepper (if needed, to taste), ladle into bowls and serve!