- Put sweet potatoes in a 4-quart saucepan and add enough water to cover them. Cook over high heat, when water comes to a boil, after 5-6 minutes reduce heat to medium-high.
- Cook for 30-35 minutes or until sweet potatoes are tender. Drain, cool slightly then peel and cut them into 2-inch pieces.
- Preheat oven to 375°F. Place sweet potatoes, salt, black pepper, cinnamon, 3 tablespoons or butter and brown sugar in a mixing bowl.
- Beat at medium speed, scraping bowl often, until smooth and combined. Transfer the mixture into a lightly greased 2-quart casserole. Cover; bake for 20-25 minutes or until cooked through.
- By then, melt remaining butter in small skillet, when sizzling, add pecans and sugar. Cook over medium-low heat, stir constantly until pecans are golden, this will take 2-3 minutes. Remove from heat.
- When about to serve, sprinkle sweet potatoes with sugared pecans and green onions.