- Preheat your oven to 350 degrees Fahrenheit. 
- Prick the sweet potatoes with a fork and bake them for about 1 hour and 15 minutes, or until they are tender. 
- After the sweet potatoes have cooled a bit, scoop the flesh into a large mixing bowl. 
- Use an electric mixer to beat them until smooth and creamy. 
- Add eggs, granulated sugar, 1/2 cup of melted butter, milk, vanilla extract, and salt to the potatoes. 
- Mix everything well until fully combined. 
- Pour the sweet potato mixture into a greased baking dish, spreading it out evenly. 
- In a separate bowl, combine the brown sugar, flour, chopped pecans, and the remaining melted butter. 
- Sprinkle this topping evenly over the sweet potato mixture. 
- Bake the soufflé for 25 to 30 minutes. 
- If the top starts browning too quickly, cover it with foil during baking.