Peel and cut sweet potatoes into chunks. Boil until fork-tender (about 20 minutes). Drain and mash until smooth.
In a mixing bowl, combine mashed sweet potatoes, sugar, butter, eggs, vanilla, and milk. Beat until creamy and spread into a greased 9×13-inch baking dish.
In another bowl, mix melted butter, brown sugar, flour, and pecans. Sprinkle evenly over the sweet potato mixture.
Bake at 350°F (175°C) for 25 minutes, until topping is golden brown and bubbly.
Let cool slightly before serving. Enjoy warm alongside your holiday main course.