Preheat your oven to 375°F and grease a 9 or 8-inch baking pan (use what you have, oval, round or rectangular).
Cook and mash the sweet potatoes. Boil the sweet potatoes in a pot of water until they're fork-tender, about 15 minutes. Then, drain them well.
3 pounds sweet potatoes
In a large bowl (or in the same pot you cooked the potatoes in), mash the sweet potatoes using a potato masher or an immersion blender.
Mix and top the casserole. Mix in the brown sugar, milk, nutmeg, butter, cinnamon, vanilla, salt, and pepper.
½ cup brown sugar, 4 tablespoon butter, ¼ cup milk, 1 teaspoon vanilla extract, ⅛ teaspoons ground nutmeg, salt and black pepper, ½ teaspoon cinnamon
Add the lightly beaten eggs and stir to combine. Spread the mixture into the prepared baking dish.
2 large eggs
Bake the casserole. Sprinkle the top with pecans, and bake for 20 minutes.
½ cup pecans
Add marshmallows and broil. Take it out of the oven, dot the top with marshmallows, and return it to the oven for another 7-10 minutes until the top is golden brown and the marshmallows are toasted.
2 cups miniature marshmallows
You can (but not essential) use a broiler setting but watch the marshmallows closely as these guys will burn quickly.