Boil Sweet Potatoes: Cook sweet potatoes (peel ON) in a large saucepan full of boiling water (to cover) until tender. Test potatoes by inserting a sharp knife deep into the middle of each one. If potatoes are done/tender enough, the knife should slide in quite easily. NOTE: Depending on the size potatoes you're using, you may need to add an additional 1-2 potatoes, if needed to ensure you have enough for 5 cups of MASHED sweet potatoes for this recipe.

Remove potatoes from the boiling water; immediately plunge them into a large bowl of ice water for 2 minutes, then remove them from the water. The peels should EASILY come off of the potatoes (discard peels).

NOTE: Once sweet potatoes have finished cooking, preheat oven to 375°F. Spray a 9" x 9" baking dish (bottom and sides) with non-stick spray.

Place sweet potatoes in a large mixing bowl; use an electric mixer on high speed to beat them until they're smooth/lump-free. **Make sure you have 5 full cups of mashed sweet potatoes before adding the remaining ingredients (measure them into a large bowl).

Add brown sugar, milk, melted (cooled) butter, eggs, salt, cinnamon and orange zest to the sweet potatoes. STIR until fully combined. Pour batter into prepared dish, distributing it evenly.

Cover dish with foil. Bake (covered) at 375°F. for 35 minutes; remove foil and bake (uncovered) 10 more minutes. Remove dish from the oven. Keep oven ON!

Sprinkle casserole with marshmallows and pecans, distributing them evenly on top. Place casserole (uncovered) back into the hot oven; bake 5-10 more minutes until done (marshmallows are golden brown and casserole is bubbly around the edges). Remove dish from the oven; let cool on a wire rack 3-4 minutes to set up a bit before serving. Serve and enjoy!