Go Back
–+ servings
Twice Baked Mashed Potato Casserole with Scallions

Creamy Twice-Baked Mashed Potatoes (Great for Leftovers!)

Print Recipe
These Twice Baked Mashed Potatoes takes creamy mashed potatoes and bakes them with cheese and green onions for the ultimate potato side dish.
Course Sides
Cuisine American
Diet Vegetarian
Keyword Mashed Potatoes, Potato, Potato Casserole, Thanksgiving Leftovers, Twice Baked Mashed Potatoes, Twice Baked Potatoes
Prep Time 25 minutes
Cook Time 30 minutes
Total Time 55 minutes
Servings 8 servings
Author Marley Goldin

Equipment

Ingredients

Homemade Mashed Potatoes

  • 2 ½ pounds potatoes russet or Yukon gold
  • ¼ cup unsalted butter softened
  • ⅓ cup milk of choice
  • 1 teaspoon garlic salt *see notes
  • ¼ teaspoon black pepper

Twice Baked Mashed Potatoes

  • 4 cups mashed potatoes leftovers, or use recipe above
  • 4 ounces cream cheese at room temperature light or regular
  • 2 ounces green onion aka scallions
  • 8 ounces cheddar cheese mild, medium or sharp-I use medium
US - Metric

Instructions

Homemade Mashed Potatoes

  • In a large pot, bring 10 cups of water to a rolling bowl.
  • Peel your potatoes and chop them into wedges to speed up the cooking time. If you like skins in your mashed potatoes, you can leave some pieces on when you peel them.
    2 ½ pounds potatoes
    Peeled potatoes cut into wedges.
  • Carefully add the prepped potatoes to the boiling water and boil for 15-20 minutes until the potatoes are fork-tender.
    Poking boiled potato with a fork to check if it's tender.
  • Once your potatoes are ready, strain and add the potato chunks to a large mixing bowl and use a potato masher or large fork to mash the cooked potato.
    Smashed Boiled Potatoes for Twice Baked Mashed Potatoes
  • Add the butter, milk, garlic salt, and black pepper and whip with a hand mixer on high until smooth and airy.
    ¼ cup unsalted butter, ⅓ cup milk of choice, 1 teaspoon garlic salt, ¼ teaspoon black pepper
    Super smooth whipped mashed potatoes

Twice Baked Mashed Potatoes

  • Preheat your oven to 350°F and grate your cheese (if using a block) and dice your scallions.
  • To a large mixing bowl, add the cream cheese and mashed potatoes and use your hand mixer on high to combine. (If you are using leftover mashed potatoes, it's okay if they are cold).
    4 cups mashed potatoes, 4 ounces cream cheese at room temperature
    Whipped Mashed Potatoes with Cream Cheese
  • Set aside half of the cheese and a handful of scallions. Use a rubber spatula to fold the rest of the cheese and scallions into the cream cheese mashed potatoes.
    2 ounces green onion, 8 ounces cheddar cheese
    Large bowl of creamy mashed potatoes with shredded cheese and green onions.
  • Transfer the potatoes into a 9 x 13 casserole dish and use your spatula to smooth out the top.
    Creamy mashed potatoes with cheese and green onions in a casserole dish.
  • Add the remaining cheese in a thin layer on top of the potatoes.
    Mashed potatoes in a casserole dish topped with a thin layer of shredded cheddar cheese.
  • Bake on the top rack for 30-35 minutes. If after 30 minutes the cheese on top is not bubbling and starting to brown, turn your oven up to broil (500°F). Watch it closely and remove from the oven immediately once the cheese starts to bubble and brown (sometimes this happens in as quick as 30 seconds!). Garnish with remaining scallions and enjoy.
    Twice Baked Mashed Potato Casserole with Scallions

Notes

  • You can make this recipe with less than 4 cups of leftover mashed potatoes! For every cup of leftover mashed potatoes, use 1 ounce cream cheese, ½ ounce scallions, and 2 ounces cheddar cheese, and adjust the casserole dish size as needed.
  • *If you don't have garlic salt on hand, you can use ½ teaspoon garlic powder and ½ teaspoon salt in place of 1 teaspoon garlic salt in this recipe. 
  • Want more spuds? Check out this list of best potato recipes!