To make sweet butternut squash with marshmallows, peel and cube one medium butternut squash, boil it until fork-tender, then mash it with melted butter, brown sugar, cinnamon, nutmeg, salt, and optional vanilla. Bake the seasoned squash in a greased 2-quart dish at 375°F until hot, add miniature marshmallows, and bake again until they are puffed and lightly browned.
This cozy casserole takes about 20–25 minutes to prepare and 45–60 minutes to cook, making 6–8 servings. The squash is naturally creamy and savory-sweet, while the brown sugar and toasted marshmallow topping add a soft, caramel-like finish that belongs on any festive dinner table.
Jump to RecipeWhy You’ll Love This Recipe
Sweet butternut squash with marshmallows is the kind of side dish that makes a holiday meal feel especially welcoming. It has the creamy texture of a classic squash mash, but the toasted marshmallow topping gives it the familiar comfort of a sweet potato casserole.
The recipe uses simple pantry ingredients and does not require complicated techniques. Brown sugar brings warm caramel notes, cinnamon and nutmeg provide gentle autumn spice, and butter rounds out the squash with a rich, silky flavor.
This casserole is also flexible enough for different dinner menus. Serve it alongside roast turkey, baked ham, pork, or a simple weeknight roasted chicken when you want a colorful vegetable side with a dessert-like touch.
If you are planning a full holiday spread, a mug of warm mulled apple cider is a lovely drink to serve with this sweet and savory dish.
Ingredients You’ll Need
The ingredient list is short, but each item has an important role in the final texture and flavor. Begin with a medium butternut squash weighing about 3 pounds, which provides enough tender flesh for 6–8 servings.
- Butternut squash: Choose a firm squash with smooth, unblemished skin and a heavy feel for its size.
- Unsalted butter: Four tablespoons add richness and allow you to control the salt yourself.
- Light brown sugar: One-third cup supplies the main sweetness and a gentle molasses-like flavor.
- Warm spices: Cinnamon and nutmeg make the squash taste especially cozy without overpowering its natural flavor.
- Salt: One-half teaspoon keeps the sweetness balanced.
- Vanilla: One teaspoon is optional, but it adds a soft bakery-style aroma.
- Miniature marshmallows: Use 1 1/2 to 2 cups, depending on how thick you want the topping.
For another ingredient idea with a warm brown-sugar character, you can find ideas for cooking with molasses. Do not substitute molasses directly for the brown sugar in this recipe unless you are intentionally changing the flavor and sweetness.
How to Make It Step-by-Step
Step 1: Heat the oven to 375°F and grease a 2-quart baking dish. A light coating of butter or nonstick spray helps the squash release easily and makes cleanup simpler.
Step 2: Peel the butternut squash with a sturdy vegetable peeler, then cut it in half and scoop out the seeds. Cut the flesh into approximately 1-inch cubes so the pieces cook at a similar rate.
Step 3: Place the cubes in a large pot and cover them with lightly salted water. Boil for 15–20 minutes, checking with a fork toward the end; the squash should be tender enough to mash without resistance.
Step 4: Drain the squash very well, allowing excess water to escape before mashing. This step matters because watery squash can make the finished casserole loose and can dilute the butter, sugar, and spice mixture.
Step 5: While the squash is still hot, mash it with 4 tablespoons melted unsalted butter, 1/3 cup packed light brown sugar, 1/2 teaspoon cinnamon, 1/4 teaspoon nutmeg, 1/2 teaspoon salt, and 1 teaspoon vanilla if using. Mash until smooth or leave a few small pieces for a more rustic texture.
Step 6: Spoon the seasoned squash into the greased 2-quart baking dish and spread it evenly. An even surface helps the casserole heat consistently and gives the marshmallows a stable layer for browning.
Step 7: Bake the dish uncovered for about 20–25 minutes, until the squash is hot in the center. If the squash was prepared ahead and is chilled, it may need additional time to heat through, so check the center before adding the topping.
Step 8: Sprinkle 1 1/2 to 2 cups of miniature marshmallows over the hot squash. Return the dish to the oven for 5–10 minutes, watching for puffed marshmallows with a light golden-brown surface.
Step 9: If you want a little more color, briefly switch to the broiler and watch continuously because marshmallows can brown very quickly. Let the casserole rest for 5 minutes before spooning it onto plates.
Pro Tips for the Best Texture
The most important preparation tip is to drain the boiled squash thoroughly. After draining, you can let it sit in the colander for a minute or two and gently shake the colander to release trapped water.
Mash the squash while it is hot so the butter melts evenly and the sugar blends into the flesh. For a smooth casserole, use a potato masher and work patiently; for a country-style texture, stop when only a few soft pieces remain.
Do not add the marshmallows at the beginning of baking. They may melt too much or burn before the squash has had time to become fully hot, so save them for the final 5–10 minutes.
If you use the broiler for extra browning, keep the oven door slightly open if your oven instructions recommend it and never walk away. The topping can change from golden to deeply browned in a short time.
For a deeper squash flavor and a less watery filling, use the alternate roasting method. Roast halved, seeded squash cut-side down at 400°F for 40–50 minutes, then scoop the cooked flesh from the skin and mash it with the listed ingredients.
Flavor Variations
The original combination is balanced and festive, but a few modest additions can give the casserole a different personality. Stir in 1/4 cup chopped pecans for a pleasant nutty contrast beneath the marshmallow topping.
For more spice, add 1/4 teaspoon ground ginger along with the cinnamon and nutmeg. Ginger provides a bright warmth that works especially well with the natural sweetness of butternut squash.
You may also replace some of the brown sugar with maple syrup for a more pronounced maple flavor. Because syrup adds liquid, make the substitution thoughtfully and continue to drain the squash well so the filling remains thick.
This dish pairs well with a holiday dessert table, especially if you also serve Christmas cookies that kids can help make. The casserole itself is sweet enough to feel special, but it still belongs beside the main course rather than replacing dessert.
Serving Suggestions
Let the casserole rest for 5 minutes after it comes out of the oven. This brief pause helps the hot squash settle and gives the marshmallow topping time to hold its shape while remaining soft.
Use a large serving spoon to scoop from the edge to the center so each portion receives both creamy squash and toasted marshmallow. A sprinkle of cinnamon over the top just before serving adds a simple finishing touch.
For a traditional holiday plate, serve it with turkey, gravy, green beans, cranberry sauce, and dinner rolls. Its sweetness is especially pleasant next to salty roasted meats and tangy cranberry dishes.
If you want a second sweet bite after dinner, small portions of old-fashioned soft cookies make a tender companion without competing with the warm spices in the squash.
Storage and Reheating
Allow leftovers to cool, then cover the baking dish and refrigerate them promptly. The casserole is best enjoyed within a few days, with the marshmallow topping becoming softer after refrigeration.
Reheat individual portions in the microwave until hot, or warm the covered casserole in the oven until heated through. If the topping needs refreshing, uncover the dish near the end of reheating and watch carefully as the marshmallows warm.
For the best make-ahead result, prepare and bake the squash mixture without marshmallows, then cool and refrigerate it. Add the marshmallows shortly before the final reheating or serving so they puff and brown instead of disappearing into the filling.
A fun dessert pairing for a larger celebration is chocolate candy-inspired cupcakes. Their rich chocolate flavor offers a delicious contrast to the buttery, warmly spiced squash.
Sweet Butternut Squash With Marshmallows
Ingredients
Method
- Heat the oven to 375°F. Grease a 2-quart baking dish and set it aside while you prepare the squash.
- Peel the butternut squash, remove the seeds, and cut the flesh into approximately 1-inch cubes.
- Place the squash in a large pot, cover it with lightly salted water, and boil for 15–20 minutes, or until the cubes are fork-tender. Drain very well.
- Mash the hot squash with the melted butter, brown sugar, cinnamon, nutmeg, salt, and vanilla if using. Leave the mixture slightly chunky or mash it smooth according to your preference.
- Transfer the squash mixture to the greased 2-quart baking dish and spread it into an even layer.
- Bake the squash uncovered for about 20–25 minutes, until the center is hot.
- Sprinkle 1 1/2 to 2 cups of miniature marshmallows over the surface. Return the dish to the oven for 5–10 minutes, until the marshmallows are puffed and lightly browned.
- For extra color, briefly use the broiler while watching the dish closely. Let the casserole rest for 5 minutes before serving.
Notes
Final Thoughts
Sweet butternut squash with marshmallows is an easy, comforting casserole with a beautiful balance of creamy squash, brown sugar, warm spice, and toasted sweetness. Boiling keeps the preparation straightforward, while careful draining ensures the filling stays thick and spoonable.
For the most reliable results, mash the squash while hot, bake it before adding the marshmallows, and watch closely during the final browning. Whether it appears at Thanksgiving, Christmas, or a regular Sunday dinner, this colorful side dish is sure to bring plenty of smiles to the table.