Boston Market Sweet Potato Casserole (Easy Copycat Recipe with Marshmallows)

Boston Market Sweet Potato Casserole is creamy, spiced sweet potatoes topped with a crunchy oat and brown sugar crumble, finished off with gooey mini marshmallows. This comforting dish is a delicious side that can easily double as dessert.

Why This Copycat Recipe Works

• Cream + eggs for smooth texture
• Oat crumble like the original
• Marshmallows layered underneath crumble (important)
• Make-ahead friendly

If there’s one holiday dish I look forward to, it’s got to be sweet potato casserole. And if you’ve ever tried Boston Market’s Sweet Potato Casserole, you know why. With its spiced sweetness and rich, comforting flavors, it’s a side dish that could easily double as a delicious dessert.

Whether you’re planning to serve it for Thanksgiving with this smoked turkey, Christmas, or just a random weeknight, this copycat Boston Market Sweet Potato Casserole is sure to be a hit with everyone at the table. Once you try it, this sweet potato casserole is sure to become one of your family’s favorites!

Ingredients for Boston Market Sweet Potato Casserole

Scroll down to the recipe card at the bottom of the page for the detailed ingredient measurements.

For the Casserole

• Sweet Potatoes: have a rich natural sweetness and creamy texture needed for this smooth casserole base. Their vibrant orange color also makes the dish visually appealing. 
• Brown Sugar: adds a caramel-like flavor that pairs well with the sweetness of the sweet potatoes and warm spices. 
• Eggs: help bind the casserole mixture by adding structure while keeping it fluffy and smooth. 
• Unsalted Butter: adds to the casserole’s creamy texture and adds a hint of savory richness that balances out the sweetness of the potatoes and sugar. 
• Heavy Cream: helps boost the casserole’s creaminess, making it smooth and indulgent while keeping it airy and light. 
• Vanilla Extract: adds a hint of floral sweetness that pairs well with the other flavors. 
• Salt: helps balance the sweetness by making sure the flavors aren’t overly sugary. 
• Nutmeg: brings a hint of spice that gives the casserole a cozy, warm flavor, adding to the overall depth of the dish. 
• Cinnamon: brings a classic flavor to your sweet potato dish by bringing warmth and an earthy flavor that pairs well with the sweetness of the casserole. 

For the Topping

• Light Brown Sugar: adds a toasty caramel flavor to the topping. You can use dark brown sugar for a stronger molasses taste. 
• All-Purpose Flour: gives structure to the topping, making it crumbly and crispy while helping hold the other ingredients together.
• Quick Cooking Oats: have a hearty and chewy texture that contrasts with the smoothness of the casserole. 
• Butter: binds the topping ingredients, adding a buttery richness that pairs well with the other ingredients. 
• Salt: brings out the caramel flavors in the sugar. 
• Cinnamon: gives the topping a warm spice that pairs well with the brown sugar and oats. 
• Mini Marshmallows: melt into a golden, gooey layer that gives the casserole its iconic texture. 

Love anything sweet potato? You have to try these sweet potato biscuits!

How to make this Boston Market Sweet Potato Casserole recipe

Make sure to scroll down to the recipe card at the end of this post for the full step-by-step instructions.

Cook the Sweet Potatoes

In a large pot, boil the washed, peeled, and cubed sweet potatoes until fork-tender. You can also bake them whole by wrapping each one in foil and then baking in a 400F oven for 55-70 minutes or until you can poke them with a knife or fork and it easily goes in. 

Make the Crumbly Oat Topping

In a large bowl, combine the brown sugar, flour, oats, cinnamon, salt, and melted butter. Stir until the mixture is crumbly and well combined. Set the bowl aside in the fridge for later.

Make the Casserole

1. Lower the oven temperature to 350F, then grease a 9x13-inch baking dish.
2. Once the sweet potatoes are cooked, allow them to cool down before mashing them with a potato masher or with an immersion blender until completely smooth
3. In a large mixing bowl, combine the mashed sweet potatoes, brown sugar, beaten eggs, melted butter, heavy cream, vanilla extract, cinnamon, nutmeg, and salt. Mix until smooth and well combined.
4. Spread the sweet potato mixture evenly into the prepared baking dish. Sprinkle with the mini marshmallows, then with the oat topping evenly, and bake in the preheated oven for 30-35 minutes, or until the topping is golden brown and the casserole is heated through.
5. Let the casserole cool slightly before serving. Enjoy!

Tips and Tricks for Perfect Boston Market Sweet Potato Casserole 

• Choose the Right Sweet Potatoes. For the best casserole, use orange-fleshed sweet potatoes, which are naturally sweet and creamy when cooked. I don’t recommend white sweet potatoes, which can be starchy and less flavorful. 
• Getting a Smooth Consistency. After cooking, let your sweet potatoes cool a little bit before mashing. Using an immersion blender or food processor will give a smoother, creamier texture than mashing by hand. 
• Chilling the Topping. For an extra crispy topping, chill your oat mixture in the fridge while you’re making your casserole. This will help the butter solidify, creating a crumbly and crunchy texture once baked. 

More Copycat Recipes You’ll Love

• Copycat Cracker Barrel Broccoli Cheese Casserole
• Outback’s Crispy Bloomin’ Onion Recipe
• The Best Red Lobster Biscuit Recipe
• Copycat Texas Roadhouse Rolls Recipe

Frequently Asked Questions - FAQ

Can I use canned sweet potatoes instead of fresh ones?

Yes, canned sweet potatoes are a convenient option, especially if you’re short on time. Just make sure that you drain and mash them well before adding them to the casserole mixture. Keep in mind that canned sweet potatoes are usually pre-sweetened, so you might want to reduce the amount of brown sugar that you use. 

How do I make the topping crunchier?

For an extra crunchy topping, try adding chopped toasted pecans or walnuts to the oat mixture. You can also sprinkle a little extra flour over the topping before baking, which will absorb the butter and make your crumble even crispier. You can also chill your topping before adding it, which will also help create a crunchy texture. 

Can I make this casserole in advance? 

Boston Market Sweet Potato Casserole is perfect for making ahead of time. Prepare the sweet potato base and topping separately, then cover them and place them in the fridge overnight. The next day, add the topping to your sweet potato mixture and then the marshmallows before baking. You may need to add an extra 10 minutes in the oven if it’s cold from the fridge.

Can I freeze Boston Market Sweet Potato Casserole?

Yes, you can freeze this sweet potato casserole. Prepare the casserole and bake it without the marshmallows. Let it cool completely, then cover and freeze for up to three months. When you’re ready to serve, thaw it in the fridge overnight, then bake until heated through. Add your marshmallows for the last 10 minutes to get the perfect golden finish.

Is Boston Market sweet potato casserole discontinued?

Boston Market has rotated this side dish seasonally in some locations, which is why many people look for a copycat version. This homemade recipe recreates the same creamy texture and marshmallow topping so you can enjoy it anytime.