Heat oil in a large soup pot or pressure cooker over medium high heat.
Cook onion and carrots until tender and lightly browned.
Add garlic, salt and spices. Cook until fragrant.
Stir in vegetable stock and yams or sweet potatoes.
Bring to a simmer. Reduce heat to simmer, uncovered, for 30 minutes until yams or sweet potatoes are tender. If you have a pressure cooker it takes about 15 minutes.
Add. tomato sauce and chopped tomatoes and return to a simmer.
Stir in sunflower seed butter.
Using a high speed blender, blend until smooth.
Taste and add salt to taste. Garnish with sunflower seeds.