Go Back
+ servings
"Make-ahead Mashed Potato Casserole"

Make-Ahead Mashed Potato Casserole

This is an easy way to prepare mashed potatoes for Thanksgiving Day!
Course Potato side dish
Cuisine American
Keyword healthy potato casserole, make-ahead mashed potato casserole, mashed potato casserole
Prep Time 20 minutes
Cook Time 1 hour 30 minutes
Total Time 1 hour 50 minutes
Servings 10 servings
Calories 269kcal
Author Joe Boyle


  • 4 lbs. russet potatoes, peeled and cut into 1 inch pieces (8 or 9 medium to med-large potatoes)
  • 2 yellow onions, coarsely chopped about 2 cups
  • 1 tbsp vegetable oil
  • 2 garlic cloves, coarsely chopped
  • 3/4 cup vegetable broth, (I use Better than Bouillon, seasoned veg. base, 1 1/2 tsp.)
  • 1/2 cup half and half
  • 8 tbsp butter
  • 1/4 cup chopped scallions, green parts only
  • 3 eggs
  • 1 1/2 tsp salt
  • pepper, if desired


  • Place potatoes in a large sauce pan or stock pot with water and 1 tsp salt. Bring to a boil and cook until soft, 15 to 20 minutes.
  • While the potatoes are cooking, place chopped onions and 1/2 tsp salt into a skillet with the vegetable oil and cook on low heat until the onions have softened,  5 to 7 minutes.
  • In a small saucepan, melt the butter, then add the half and half and 1 cup of the vegetable broth, keep warm.
  • Once the onions are done, place them into a food processor along with the garlic and the remaining vegetable broth. Chop until the onions are finely chopped.
  • Drain the potatoes, add the onions and the melted butter with the liquids. Use a hand mixer to mash them until they are smooth.  Let the potatoes cool. (I put 4 inches of cold water in the sink and placed the pot into it for 15 minutes).
  • Add the eggs one at a time and mix them in. (Alternatively, you could use 4 to 6 ounces of softened cream cheese rather than the eggs.  The eggs give the potatoes an airy lift while the cream cheese would not.  Both would be equally good).  Taste the potatoes and adjust salt and pepper seasoning.
  • Add the scallion greens and fold in with a spoon or spatula.
  • Spray cooking oil in a 3 quart casserole dish and add the mashed potatoes. Cover with plastic wrap and store in the refrigerator overnight.
  • Take the potatoes out of the refrigerator at least one hour before placing in the oven.  Use a spoon or fork to make peaks, then place into a 350 degree oven for 45 minutes until the potatoes are warm and the peaks are starting to brown. (If you make this the same day, allow 30 to 35 minutes in the oven).
  • Serve hot.


  1. Adapted from Cook's Country.
  2. Leftover mashed potatoes can be kept in an airtight container in the refrigerator for 3 days. Reheat in a microwave.


Calories: 269kcal