4 sweet potatoes (3.5 to 4.5 pounds total)
3 tablespoons butter
2 tablespoons brown sugar
1 ½ teaspoon salt
1 ½ teaspoon ground cinnamon
½ teaspoon ground ginger
1/8 teaspoon freshly ground black pepper
1/8 teaspoon ground nutmeg (optional)
1/8 teaspoon ground cloves (optional)
1/8 teaspoon ground allspice (optional)
¼ teaspoon cardamom (optional)
1 teaspoon vanilla
2 tablespoons cognac (can substitute brandy or bourbon whiskey)
2 large eggs
Preheat oven to 400 degrees F. Scrub sweet potatoes well to remove dirt. Prick each one several times with a fork. Place on a foil lined sheet pan. Bake until a knife inserted in the center of the largest sweet potato goes through easily, 45 minutes to an hour. Remove from oven and allow to cool enough to handle. Gently peel the skins away from the potatoes, or cut the potatoes in half and carefully scoop out all the flesh. Discard skins.
While still warm, mash the potatoes until smooth, add butter and stir to melt. Add remaining ingredients and stir until very well combined.
Butter an 8-by-8-inch casserole dish. Pour the sweet potato mixture into the casserole dish and top with the streusel topping.
¾ cup butter at room temperature
¾ cup brown sugar
¾ cup all-purpose flour
½ teaspoon ground cinnamon
¼ teaspoon salt
1 cup toasted pecan pieces
1 cup miniature marshmallows
Mix butter, brown sugar, and flour with a pastry blender or two forks until it's crumbly-looking. Add cinnamon, salt, pecans, and marshmallows. Fold together to mix well. Sprinkle evenly over the sweet potato casserole.
Reduce oven temperature to 350 degrees F and bake for around 30 minutes, until casserole is hot and topping is beautifully golden brown.
This is a great holiday casserole because it's very forgiving when multiple dishes are fighting for oven time. It "plays well with others" and can be cooked at a temperature of anywhere from 350 to 400, just keep a closer eye on it if you cook it at the higher temperature so the topping doesn't burn. After the first 15 minutes be sure to take a peek every 5 minutes.