Preheat oven to 400. Put the sweet potatoes on a baking sheet and pierce each one 2 to 3 times with a fork. Bake for 45 to 60 minutes or until tender. Set aside to cool.
Turn the oven down to 350. Scoop the sweet potato out of their skins and into a medium bowl. Discard the skins. Mash the potatoes until smooth. Add the eggs,butter,brown sugar,salt,cinnamon,ginger,nutmeg, and pepper to taste. Whisk the mixture until smooth.
Butter an 8x8 inch casserole. Pour the sweet potato mixture into the pan and sprinkle the top with the pecans. Bake for 30 to 40 minutes until a bit puffy. Serve immediately.