Peel and quarter the sweet potatoes.

Cook sweet potatoes in boiling water in a 3-quart saucepan for 15 minutes or until tender.

Drain the cooked sweet potatoes.

Heat olive oil in a large nonstick skillet on medium-high heat.

Add finely chopped onion to the skillet.

Cook and stir the onion for 4 minutes, until softened.

Add curry powder to the skillet.

Cook for an additional 2 minutes, stirring frequently, until fragrant.

Remove the skillet from heat.

Mash the cooked sweet potatoes thoroughly.

Stir in the onion mixture, sour cream, and salt (if desired) into the mashed sweet potatoes.

Serve immediately.