Martha Stewart's mashed sweet potato casserole recipe consists of sweet potatoes, whole milk, butter, nutmeg, marshmallows and seasonings. This casserole takes about 55 minutes to prepare and serves about 8 people.
To make the casserole, preheat your oven to 375 F. Peel and cut about 8 sweet potatoes and cut into 1-inch pieces. Place them in a large saucepan, cover with an inch of cold water, and add salt. Bring this to a boil, and then simmer for about 15 to 20 minutes or until the sweet potatoes are soft. Drain the sweet potatoes, and place them back in the pan. Let the liquid evaporate from the pan by cooking over medium heat for about 2 minutes.
Next, take the pan off heat and pour 1/2 cup of milk, 4 tablespoons of butter and 1/2 teaspoon of nutmeg to the mixture. Mash until it is a smooth consistency. Season with salt and pepper before moving this mixture to a 2-quart baking dish. Place 2 cups of mini marshmallows on the casserole. Place in the oven, and bake for about 15 to 20 minutes or until the marshmallows are lightly browned. For extra sweetness, you can use cinnamon in place of nutmeg and add 1/3 cup of brown sugar. The casserole is now ready to eat.