Can I make the casserole ahead of time?

Yes, prepare and store the filling and topping separately, and assemble just before baking.

Can I use canned sweet potatoes?

Since canned sweet potatoes are usually packed in syrup, you would need to drain them well and cut back on the sugar in the recipe.

If the filling is still quite hot when you add the topping, it may sink slightly. Cool the sweet potato mixture a bit before adding the topping.