Preheat oven to 350ºF.
Peel and dice 3 pounds of sweet potatoes.
In a large pot, cover sweet potatoes with water and boil until tender (about 15 minutes).
Drain water off potatoes and mash until large clumps are gone.
In a large bowl, measure out at least 4 cups of cooked and mashed sweet potatoes (this does not need to be exact).
Add in sugar, milk, butter, eggs, and vanilla and mix well with an electric hand mixer.
Spread mixture into a greased 9″ x 13″ baking dish.
In the same bowl, mix topping ingredients together until mixture feels like coarse sand, then sprinkle over sweet potato mixture.
Bake in preheated oven for 45 minutes.