I found this recipe on some AOL site a few years back. That site appears to be gone, but a search for "Gwen's sweet potato pie" recipe shows that it has been spread around a few recipe sites. I've made a few tweaks. Please note this makes two pies.
3 lbs sweet potato
1 stick butter
1 1/2 cup sugar
1 can sweetened condensed milk
2 eggs
1 tsp vanilla
~1 1/2 tsp various spices (see note)
Boil the sweet potato, skin on, until they're soft all the way through when poked with fork. Put them in a colander, and while running cold water over them, take the skin off. This is easier than it sounds; it just kind of slides right off.
Blend or otherwise mush the sweet potato. Add butter, blend thoroughly. One at a time, add sugar, milk, eggs, and vanilla, blending thoroughly after each.
Now you add spices, and you can really wing it here. Original recipe called for all nutmeg. The other day I used 1 tsp clove, 1/2 tsp cinnamon, and whatever ginger I had left (not quite 1/2 tsp), and I was really pleased with the results. You might consider some allspice if you've got it handy.
The original recipe notes that your filling should be smooth when you're done, not unlike a cake batter. You should be able to pour it easily, but it shouldn't be thin or runny. I've never had any trouble at this stage, so I can't really recommend action to take if it needs fixing.
Pour into two prepared 9 or 10 inch pie shells. I strongly recommend deep dish style; the results are significantly more satisfying. Sprinkle cinnamon over the top of the pie, bake for 50 minutes to 1 hour. Let cool for at least one hour before eating. Serve warm or cold or with ice cream; it's going to be delicious no matter what.
Edit 11/23/11: Fixed the comma splice in the first paragraph of the instructions. I'm a nerd.
