Bake potatoes at 375 for about 90 minutes, or until a knife can be inserted in the middle fairly easily. Allow to cool at least 20-30 minutes, or until you can handle them.
Heat oven to 400 degrees.
Grease a 2 quart baking dish. The dish should be no more than 3 inches deep. Set it aside for now.
Cut potatoes in half and scoop insides into a large bowl. Add eggs, sugar, salt, vanilla, and milk.
Mash together with a potato masher. Mix until it is well combined and somewhat smooth. Little lumps are fine. Pour into the baking dish.
In another bowl, mix together the brown sugar, flour, pecans, and cinnamon. Add in the butter. Mix until it is a crumbly, doughy mixture. This is most easily done by hand. Crumble over the top of the potato mixture.
Bake for 30-40 minutes, or until the top is golden brown.