1. Cover potatoes with water in a small saucepan; bring to a boil. Reduce heat, and simmer 14 minutes or until tender. Drain and return to saucepan.
2. Heat butter in a large nonstick skillet over medium-high heat. Add onion; cook 12 minutes or until golden, stirring frequently. Set aside.
3. Add milk, salt, and pepper to potatoes. Mash the mixture with a potato masher or fork to desired consistency. Stir in onions.