1. Wash hands with warm water and soap.
2. Using a clean vegetable brush, gently wash sweet potatoes. Leave skins on, and cube sweet potatoes.
3. Add water and potatoes into a large cooking pot and bring to a rolling boil over high heat. Then lower heat to a simmer and cook potatoes for 15 to 20 minutes or until tender.
4. Drain and allow potatoes to cool. Once cooled, mash and set aside.
5. Preheat the oven to 350F.
6. Butter a 2-quart oblong baking dish and set aside.
7. In a microwave-safe bowl, melt 2 tablespoons of butter.
8. Whisk together eggs, vanilla, milk, and butter in a large bowl.
9. Wash hands with soap and water after handling eggs. Then add the potatoes to the mixture. Transfer to the prepared baking dish and set aside.

Topping

1. Wash hands with warm water and soap.
2. In a microwave-safe bowl, melt 4 tablespoons of butter.
3. Chop pecans and set aside.
4. Combine flour, brown sugar, cinnamon, and butter in a medium bowl. Mix until the mixture clumps together.
5. Sprinkle over the top of the sweet potato mixture in an even layer, then sprinkle pecans.
6. Bake for 25 to 30 minutes or until mostly set in the center and golden on top. Serve hot.

Storage: Store in the refrigerator 4 days, or freeze for longer storage.