Sweet Potato Casserole with Walnuts and Brown Sugar

This sweet and savory sweet potato casserole with walnuts and brown sugar oat topping is sweet, buttery and made a little bit lighter than the traditional holiday classic. It’s a family favorite comforting dish that’s perfect for your Thanksgiving table or any special occasion!

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A close up shot of sweet potato casserole with walnut topping being scooped by a wooden spoon.

Why you’ll love it

This sweet potato casserole is easy, a little bit lighter than most traditional sweet potato casserole recipes, and absolutely delicious. It’s the perfect balance of sweet and savory. This one is sure to be a family fave.

It’s also the perfect Thanksgiving side dish because you can make your life easier by prepping this one ahead. Just assemble it the night before (don’t bake it), keep it in the fridge covered, and stick it in the oven when it’s time.

The sweet potato base is creamy and buttery and the crunchy brown sugar walnuts topping adds the perfect amount of sweet, buttery, nutty crunch.

If you’re looking for an alternative to the classic sweet potato casserole with marshmallows, you won’t be disappointed with this one.

Ingredients for sweet potato casserole with walnut topping laid out on a wooden tabletop with labels.

Ingredients you’ll need

Filling ingredients

  • Large sweet potatoes
  • Pure maple syrup
  • Butter
  • Milk
  • Vanilla
  • Cinnamon
  • Salt 

Crumble topping ingredients

  • Rolled oats
  • White whole wheat flour
  • Brown sugar
  • Walnuts
  • Cinnamon
  • Salt
  • Butter

I love using white whole wheat flour because it’s more nutrient dense but performs super similarly to regular whole wheat. King Arthur is my favorite brand that makes it.

If you prefer a creamier mashed potato mixture, use heavy cream instead of milk. For dairy-free, use almond milk or oat milk and a vegan butter.

Step-by-step instructions

Make the filling

  1. Preheat the oven to 350 degrees.
  2. Boil a large pot of water and add sweet potatoes. Boil on high heat until sweet potatoes are fork tender, about 10-15 minutes.
  3. Drain the sweet potatoes well and add the rest of the filling ingredients to the pot (maple syrup, butter, milk, vanilla, cinnamon, and salt). If you prefer, transfer to a large bowl first. Using an electric mixer or potato masher, combine the ingredients well and mash potatoes until smooth. You can also use a food processor.
A pot of cubed sweet potatoes cooked with maple syrup, cinnamon added.
A pot of sweet potatoes being mashed.

Make the topping

  1. Next, make the crumble topping in a medium bowl. Add rolled oats, white whole wheat flour, brown sugar, walnuts, cinnamon, salt and butter.
  2. Combine well (I prefer to use clean hands) until the topping has a crumbly “wet sand” consistency.
Sweet potato casserole topping ingredients in a small bowl, unmixed.
Sweet potato casserole crumble walnut topping mixed in a bowl.
  1. Next, add the sweet potato mixture to a large casserole baking dish that’s been sprayed or coated with oil or butter and smooth the top with a silicone spatula.
  2. Add the walnut topping in an even layer to the top of the sweet potato mash.
A casserole dish full of sweet potato mixture unbaked.
Sweet potato casserole mixture with topping added.
  1. Bake for 30-40 minutes until topping is golden brown. Enjoy!
Baked sweet potato casserole with walnut topping in a white casserole dish.

Recipe tips

  • If you like your sweet potato filling to be sweeter, add 1-3 additional tablespoons of maple syrup. If you’d like no added sugar, simply omit the maple syrup altogether.
  • Add a handful of mini marshmallows to the topping if you like the classic marshmallow sweet potatoes.
  • If prepping the night before, note that your bake time may be a little different. It’s a good idea to start checking on the casserole around the 25 minute mark to prevent burning.
  • If your topping is browning too fast, simply cover with aluminum foil to slow it down.
  • Swap in any other nuts that you enjoy like pecans or almonds.
  • Store leftovers in an airtight container for up to 5 days.
  • The best part about including this at your Thanksgiving dinner table is that you can prep it ahead the night before, simply prepare your mashed sweet potatoes, topping, and then assemble in a casserole dish. Cover with plastic wrap and store in the fridge. Bake when it’s time the next day!
Sweet potato casserole with walnut topping on a white plate with a fork.

What to serve it with:

Crispy Parmesan Carrot Sticks

Creamy Garlic Cottage Cheese Mashed Potatoes

Crispy Smashed Broccoli Parmesan with Lemon and Garlic

Perfectly Cooked Thin Sliced Chicken Breast (Air Fryer Recipe)

Arugula Pear Salad with Toasted Pecans & Feta Cheese

A close up shot of sweet potato casserole with walnut topping being scooped by a wooden spoon.

Sweet Potato Casserole with Walnuts and Brown Sugar

Sweet potato casserole made a little bit lighter with a walnut brown sugar topping.
5 from 1 vote
Print Pin Rate
Prep Time: 10 minutes
Cook Time: 35 minutes
Servings: 8

Ingredients

Filling

  • 4 large sweet potatoes peeled and cubed
  • 1 tbsp maple syrup
  • 1 tbsp butter
  • 1/2 cup milk
  • 1 tsp vanilla
  • 1/2 tsp cinnamon
  • 1/2 tsp salt

Crumble topping

  • 1/2 cup rolled oats
  • 1/3 cup white whole wheat flour can sub regular flour or whole wheat
  • 1/4 cup brown sugar
  • 1/2 cup walnuts chopped
  • 1/2 tsp cinnamon
  • 1/4 tsp salt
  • 1/4 cup butter diced

Instructions

  • Preheat the oven to 350 degrees.
  • Boil a large pot of water and add sweet potatoes. Boil on high heat until sweet potatoes are fork tender, about 10-15 minutes.
  • Drain the sweet potatoes well and add the rest of the filling ingredients to the pot (maple syrup, butter, milk, vanilla, cinnamon, and salt). Using a handheld mixer or potato masher, combine the ingredients well and mash potatoes until smooth.
  • Next, make the crumble topping in a medium sized bowl. Add rolled oats, white whole wheat flour, brown sugar, walnuts, cinnamon, salt and butter.
  • Combine very well (I prefer to use clean hands to thoroughly incorporate the butter) until the topping has a crumbly "wet sand" consistency.
  • Next, add the sweet potato mixture to a large casserole dish that's been sprayed or coated with oil or butter and smooth the top with a silicone spatula.
  • Add the crumble mixture evenly to the top of the sweet potato mixture.
  • Bake for 30-40 minutes until topping is golden brown. Enjoy!
Course: Side Dish

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It's me, Jamie!

I’m a Registered Dietitian dedicated to helping you break free of the all-or-nothing dieting with balanced and realistic healthy eating.

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Meet Jamie

I’m a Registered Dietitian and I’ve been exactly where you are, right now. The all or nothing dieting, the constant food guilt, the scale obsession, absolutely no balance with food…. Sound familiar?