Boston Market Sweet Potato Casserole Easy Copycat Recipe

The sweet potato casserole on the Boston Market holiday menu is the one side dish that runs out before anything else on the table. This copycat version layers a smooth, brown-sugar-sweet potato base under a blanket of marshmallows and a buttery oatmeal cookie crumble that bakes up crisp. Baking the sweet potatoes whole rather than boiling them keeps the flesh dense and sweet, which is why this tastes closer to the restaurant’s than most homemade versions. It serves twelve from one 9×13 pan, so it covers Thanksgiving, Christmas dinner, or a potluck without doubling anything.

This post contains affiliate links. As an Amazon Associate, I earn from qualifying purchases.

Why this recipe works

The magic happens in three distinct layers that complement each other perfectly. The sweet potato base gets its luxurious texture from proper roasting and mashing with butter and cream, while warm spices add depth without overwhelming the natural sweetness. The marshmallow layer provides a nostalgic comfort-food element, and the oatmeal crust delivers a satisfying crunch that contrasts beautifully with the soft interior. This combination creates a dish that’s both elegant enough for special occasions and comforting enough for everyday enjoyment.

Ingredients

For the Sweet Potato Base:

• Sweet potatoes – Provide the creamy, naturally sweet foundation of the dish
• Butter – Adds richness and helps create smooth, luxurious texture
• Eggs – Bind ingredients together and create a custard-like consistency
• Salt – Enhances natural sweetness and balances all flavors
• Ground cinnamon – Adds warmth and classic holiday spice notes
• Ground nutmeg – Contributes aromatic depth and complexity
• Vanilla extract – Enhances sweetness and adds aromatic richness
• Dark brown sugar – Provides molasses notes and deeper sweetness
• Heavy cream – Creates ultra-smooth, restaurant-quality texture

For the Oatmeal Crust:

• All-purpose flour – Forms the base structure of the crunchy topping
• Quick-cooking oats – Creates a signature texture and nutty flavor
• Dark brown sugar – Sweetens the crust and helps with browning
• Butter – Creates a crumbly texture when worked into dry ingredients
• Ground cinnamon – Unifies flavors throughout the dish
• Salt – Enhances the crust flavors and balances the sweetness

For Assembly:

• Miniature marshmallows – Provide the classic sweet, gooey middle layer

Ingredient Notes

• Use dark brown sugar, not light. The molasses content is what gives both layers their color and their depth, and light brown sugar makes the casserole taste noticeably thinner.
• Quick-cooking oats are correct here. Old-fashioned rolled oats stay tough in a topping that bakes for only 30 to 45 minutes, and instant oatmeal packets turn to paste.
• Miniature marshmallows melt evenly. Standard-size marshmallows leave gaps of bare potato between puddles.
• Canned sweet potatoes work in a pinch, but drain the syrup thoroughly and expect a softer, sweeter result.

How to Make Boston Market Sweet Potato Casserole

1. Wrap sweet potatoes in foil, place them on a baking sheet, and bake at 350 degrees for about an hour, until they are easily pierced with a fork.
2. Allow the sweet potatoes to cool until they are cool enough to handle.
3. Remove the foil and the sweet potato skins.
4. Place the cooked sweet potatoes into a large bowl.
5. Mash the sweet potatoes with butter until mostly smooth.
6. Add eggs, salt, cinnamon, vanilla, and nutmeg, and beat until a uniform mixture forms.
7. Add brown sugar and cream and mix well.
8. Combine the flour, brown sugar, salt, oats, and cinnamon in a medium bowl and stir until well combined.
9. Stir in butter with a fork until you have a crumbly mixture.
10. Lightly coat a 9×13-inch baking pan with cooking spray.
11. Spread the sweet potato mixture in the pan.
12. Top with the marshmallows, then crumble the oatmeal crust over them.
13. Bake at 350°F for 30 to 45 minutes.

Make-ahead Strategy

For optimal results, bake the casserole thoroughly and then refrigerate. Reheat gently in the oven the next day. The raw eggs make it inadvisable to assemble and refrigerate an unbaked casserole overnight, as this affects both safety and texture.

Storage & reheating instructions for the Boston Market Sweet Potato Casserole

• Refrigerator Storage: Store covered casserole in the refrigerator for up to 4 days after baking
• Reheating Method: Reheat, covered, in a 350°F oven for 20-25 minutes, until heated through. For a crispier top, uncover for the last 5 minutes of reheating.
• Freezing: Wrap tightly and freeze for up to 3 months. Thaw completely before reheating.

Love Boston Market? Try these copycat recipes!

• Boston Market Squash Casserole
• Boston Market Creamed Spinach
• Boston Market Macaroni and Cheese
• Boston Market Cornbread
• Boston Market Meatloaf

Be sure to check out more of my easy casserole recipes and the best restaurant copycat recipes here on CopyKat.com!

About Boston Market

As everyone knows, Boston Market is not just in Boston. It’s a chain of fast-casual stores that specializes in rotisserie chicken and other meat dishes, along with a choice of sides. However, the founders, Arthur Cores and Steven Kolow, did reside in Boston.

Their concept was to provide fresh, healthy food delivered quickly at prices closer to those of your typical fast food.