https://tastesbetterfromscratch.com/sweet-potato-casserole/

Cook Potatoes: Place the sweet potatoes in a large pot. Add enough water to the pot to cover the potatoes a little more than half way. (You will need at least 3-4 inches of water but the water will not completely cover the potatoes!) Bring the water to a boil and then turn the heat to a medium simmer. Cover and simmer until they feel tender when poked with a fork. It may take 20-40 minutes to cook your sweet potatoes depending on the size of the potatoes, but you don't want them to be mushy.

Peel Potatoes: Drain water and place sweet potatoes on a plate or cutting board to cool down. Once they are cool enough to handle, peel and discard the skin from the potatoes and place potatoes in a large mixing bowl.

Mix: Add eggs, evaporated milk, vanilla, sugar, salt, and butter and mash everything together until smooth. I start with a potato masher, and then use an electric mixer on low speed, for about 45 seconds, to get the mixture smooth.

Pour mixture into a lightly greased casserole dish. Anything around the size of an 8×11'' , 9×13'' or even a deep dish 10'' pie pan will work.

Make Topping: Add flour, brown sugar and pecans to a mixing bowl. Add butter and cut in with a fork or pastry blender until well combined. Sprinkle topping over sweet potato mixture.

Bake at 350 degrees F for 35-40 minutes.