First, peel and chop the sweet potatoes. Then, add them into the crockpot and add the water.
Now, cook on high for 3 hours or until all the sweet potatoes have softened. Then, carefully drain the water from the crockpot. Be very careful because everything is hot. Make sure you have a good grip on the crockpot because the glass can be slippery.
Next, with a potato masher, mash the sweet potatoes together. It's doesn't have to be smooth and free of lumps.
Then, add in the granulated sugar, butter, vanilla extract and salt to taste.
Now, mix together all the ingredients for the topping together and place them across the top of the mashed sweet potatoes.
Cover the crockpot and cook and additional hour.
Lastly, allow thy casserole to cool because everything will be extremely hot.