This is the Allrecipe's Gourmet Sweet Potato Classic but modified so that your sweet potatoes are actually cooked through and will mash easily. This is a very sweet dish, so the sugar could be at least cut in half.
5 sweet potatoes
1/4 teaspoon salt
1/4 cup butter
1 teaspoon vanilla extract
1/2 teaspoon ground cinnamon
1/2 cup white sugar (you could use brown sugar instead)
2 tablespoons heavy cream
1/4 cup butter, softened
3 tablespoons all-purpose flour (whole wheat flour works too)
3/4 cup packed brown sugar (light or dark, your preference)
1/2 cup chopped pecans (optional)
Preheat oven to 450 degrees F. Roast sweet potatoes 1 hour. Cool slightly, peel, and mash.
Lightly grease a 9x13 pan. In a large bowl, mix the mashed sweet potatoes, salt, 1/4 cup butter, eggs, vanilla extract, cinnamon, sugar, and heavy cream. Transfer to the prepared baking dish. In a medium bowl, combine 1/4 cup butter, flour, brown sugar, and chopped pecans. Mix with a pastry blender or your fingers to the consistency of course meal. Sprinkle over the sweet potato mixture. Bake 30 minutes in the preheated oven, until topping is crisp and lightly browned.