Heat olive oil in a large saucepan over medium heat. Cook onion, stirring, for 5 minutes or until translucent. Add cumin and cook, stirring for 1 minute or until aromatic.
Add pumpkin and stir to coat. Add stock. Simmer for 20 minutes or until the pumpkin is soft. Set aside to cool slightly. Using a blender, blend until smooth.
Serve with a spoonful of yoghurt on top and a slice of crusty toast.