Preheat oven to 375º
Wash the potatoes then pat dry. Rub each of the potatoes with the oil, then place on a baking pan and bake for 35 to 40 minutes. Remove potatoes from the pan,(carefully) split in half and remove the insides from the skin. Place into a large bowl and set aside to cool. When the potatoes are cool, add the fine sugar, milk, eggs, vanilla, salt and mix well until smooth.
In a separate bowl add the light brown and brown sugars, flour, and butter. Using a large fork mix until it forms a crumb like consistency.
Pour the potato mix into a square oven safe baking dish and top with the crumb. Bake for 35 minutes. Top with crumbled pecans and serve.