This sweet potato casserole is sprinkled with a nutty crumb topping to create a pleasantly crunchy contrast to the creamy and soft mashed sweet potatoes down below. The filling gets an extra special pumpkin pie(ish) treatment with brown sugar and vanilla for a deep caramel flavor. (In fact, leftovers can be heated up and topped with a scoop of ice cream just like pie.) Want to make ahead for Thanksgiving or another special holiday? Not a problem. The casserole ingredients can be mixed and transferred to a baking dish. Cover and refrigerate until ready to bake but leave off the topping. Store it separately at room temperature in an air-right container and sprinkle it on right before baking.
Ensure sweet potatoes are cooked until very tender for a perfectly smooth, creamy filling—any lumps will detract from the texture. When preparing the topping, combine ingredients just until moist and clumpy; overmixing can create a paste rather than a desirable crumbly texture. For enhanced flavor, consider adding a pinch of cinnamon or nutmeg to the sweet potato filling, complementing the brown sugar and vanilla notes. This casserole is excellent for make-ahead preparations: assemble the filling and store covered in the fridge, keeping the topping separate at room temperature. Sprinkle the topping just before baking for maximum crunch.