Heat butter in a large pan over medium-high heat, add onion, and cook until golden-brown, about 5 minutes.

Add garlic and cook 1 minute more. Stir in curry powder, salt, and pepper. Add pumpkin and potatoes and cook for 5 minutes, stirring frequently.

Pour in broth and raisins, cover, and reduce heat to medium. Replace cover and continue to cook until pumpkin and potatoes are tender, 5 to 10 minutes more. Garnish with cilantro.