Sweet Potato, Mushroom, Leftover Turkey Casserole

Leftover turkey casserole with bacon, onions, mushrooms, mashed sweet potatoes, Gruyere cheese, and a buttery cracker topping

Sweet Potato Mushroom Leftover Turkey Casserole
Elise Bauer

You know what happens when a few people cancel at the last minute for Thanksgiving?

Lots of leftovers, that's what!

This is a good thing. Leftover cooked turkey is wonderfully versatile. You can put it in soups, tacos, chili, sandwiches, or make something like this, a hearty turkey casserole.

This casserole is loaded. You start with bacon and build from there. Onions, mushrooms, mashed sweet potatoes, Gruyere cheese—everything gets mixed in with the chopped up leftover turkey, spread into a casserole dish, top it with crushed saltines and butter, and bake. Yum!

Happy Thanksgiving everyone!

Sweet Potato, Mushroom, Leftover Turkey Casserole

Prep Time 20 mins
Cook Time 80 mins
Total Time 100 mins
Servings 6 to 8 servings

This recipe uses mashed sweet potatoes. You could easily substitute regular mashed potatoes for the sweet potatoes if you want.


  • 1/4 lb bacon, cut into half inch slices
  • 1 large yellow onion, peeled and chopped
  • 2 cups roughly chopped leftover (cooked) turkey meat (light and/or dark meat)
  • 3 to 4 cups of mashed cooked sweet potatoes or garnet yams (from about 2 large sweet potatoes)*
  • 1 lb of sliced cremini or button mushrooms
  • 1/2 teaspoon salt
  • 1/4 teaspoon freshly ground black pepper
  • 1 1/2 cups (6 ounces) grated Gruyere cheese
  • 20 saltine crackers
  • 4 Tbsp butter, divided, plus more to grease the baking pan
  • *To cook the sweet potatoes, peel them, slice them into 1-inch thick disks, toss with some olive oil, place them in a single layer in a roasting dish covered with foil and roast them at 400°F for 20 minute or until fork tender. Or you can pierce the whole unpeeled sweet potatoes with a fork all over, wrap in foil and roast at 350°F for an hour or until fork tender. Or, you can peel and chop them and boil them until tender. Then mash.


  1. Cook the bacon and onions:

    Place bacon in a large sauté pan on medium heat. Cook until almost crispy and most of the fat has rendered out, about 8 to 10 minutes. Add the chopped onion to the pan with the bacon. Continue cooking until the onion is golden brown, about 10 minutes. Transfer bacon and onions to a bowl, stir in the chopped leftover turkey, and set aside.

  2. Sauté mushrooms:

    In the same pan, add a tablespoon of olive oil. Heat on high heat. Add the mushrooms and sauté until lightly browned and beginning to give up their moisture, about 5 minutes.

  3. Mix the mushrooms in with the turkey bacon onion mixture. Mix the mashed cooked sweet potatoes in with the mushrooms and turkey:

    Stir in 1/4 cup of water (or stock if you have some).

  4. Preheat oven to 350°F. Butter a 8x12 baking dish and spread the turkey sweet potato mixture in it in an even layer
  5. Make topping:

    To make the casserole topping, place the Gruyere cheese, saltine crackers and 2 Tbsp of butter in a food processor and pulse until crumbly. (Or you can crumble the saltines with your hands and place everything in a large bowl and mix until crumbly.)

  6. Spread the topping over the casserole:

    and dot with the remaining 2 Tbsp of butter.

  7. Bake:

    Bake uncovered at 350°F for 45 to 50 minutes, until the topping is golden brown.

Sweet Potato Mushroom Leftover Turkey Casserole
Elise Bauer