All food items (or software, as Alton Brown puts it) needed:
4 c sweet potatoes
1/2 c white sugar
1/2 c packed brown sugar
1/3 c all-purpose flour
2 eggs
1/2 tsp salt
1/2 tsp vanilla
7 TBS butter
1/2 c milk
1/2 c chopped pecans
I originally found the recipe at allrecipes.com, but I made some minor changes.

4 c sweet potatoes, cubed (I did a few more)
1/2 c white sugar
2 eggs, beaten
1/2 tsp salt
4 TBS butter, softened
1/2 c milk (I used coconut milk. Truly good stuff.)
1/2 tsp vanilla

Preheat oven to 325 degrees.

Put potatoes in a medium saucepan with water to cover. Cook over medium heat until tender; drain and mash. (I cannot remember how long. Not 30 minutes, though.)

In a large bowl, mix: sweet potatoes, white sugar, eggs, salt, 4 TBS butter, milk, and vanilla. Mix until smooth. Transfer to a baking dish. (They said 9×13. I think mine was a little larger.)

For the topping:
1/2 c packed brown sugar
1/2 c all-purpose flower
3 TBS butter, softened
1/2 c chopped pecans

In a medium bowl, mix brown sugar and flour. Cut in butter till mixture is coarse. Stir in pecans. Sprinkle on top of sweet potatoes.

Bake in the preheated oven 30 minutes, or until topping is golden brown.

recipe
receipt