Slow Cooker Sweet Potato Casserole Recipe: Easy Marshmallow Holiday Side

I made this Slow Cooker Sweet Potato Casserole Recipe last Thanksgiving, and it completely freed up my oven. The whole kitchen smelled like brown sugar and warm spice while I worked on everything else. I stirred it once, topped it with marshmallows, and watched my family go back for seconds.

It tastes like the classic holiday side, but it asks for far less effort from me. If you want one of the easiest crockpot sweet potato recipes out there, I promise this one delivers.

Cooking Time

Good news: most of the time here is hands-off. Here is how the clock breaks down.

• Prep Time: 20 minutes
• Cooking Time: 3 hours 30 minutes (on High)
• Total Time: 3 hours 50 minutes

Ingredients You’ll Need

This recipe uses only eight ingredients, and you probably have most of them already. If you love crockpot sweet potatoes with brown sugar and butter, this list will feel very familiar.

• 3/4 cup packed brown sugar: Add deep molasses flavor; pack it firmly into the cup.
• 2 tablespoons butter: Gives the sauce a rich, silky finish.
• 1 tablespoon pumpkin pie spice: Brings that cozy holiday flavor in one easy scoop.
• 1 teaspoon salt: Balances the sweetness so the dish never tastes flat.
• 1 tablespoon water: Helps the sugar and butter melt into a smooth sauce.
• 1 tablespoon vanilla: Add warmth and depth; stir it in after microwaving.
• 3 1/2 pounds sweet potatoes, peeled and diced into 1/2-inch cubes: Cut them evenly so every piece cooks at the same speed.
• 2 cups miniature marshmallows: The classic gooey topping; add them only at the very end.
• Cooking spray: Keeps the slow cooker from sticking and makes cleanup easy.

Note: serves several (about 14 half-cup portions)

Equipment You Need

You don’t need fancy tools for this one. A few basics will do the job.

• 5-quart oval slow cooker: Cooks the potatoes gently and evenly with no babysitting.
• Large microwavable bowl: Melts the sauce and holds the potatoes while you coat them.
• Vegetable peeler: Removes the skins quickly.
• Sharp knife and cutting board: Help you cut the potatoes into even cubes.
• Measuring cups and spoons: Keep the sweet, salty, and spicy flavors balanced.
• Large spoon or spatula: Stirs the sauce and coats every cube.

How to Make Slow Cooker Sweet Potato Casserole?

This recipe comes together in a few simple steps. You make a spiced brown sugar sauce, toss it with the potatoes, and let the slow cooker do the rest. The marshmallows go on right at the end. Follow the steps below and you will get tender, glossy sweet potatoes every time.

Step 1: Prep the Slow Cooker

Spray the inside of your 5-quart oval slow cooker with cooking spray. Be generous and reach up the sides a little. This tiny step makes cleanup so much faster later.

Step 2: Cube the Sweet Potatoes

Peel the sweet potatoes and cut them into 1/2-inch cubes. I slice a thin piece off one side so the potato sits flat on the board. That flat edge keeps it from rolling, which makes cutting safer and easier.

Step 3: Melt the Brown Sugar Sauce

In a large microwavable bowl, mix the brown sugar, butter, pumpkin pie spice, salt, and water. Microwave it uncovered on High for 1 1/2 minutes, stirring once halfway through. The mixture should look warm, smooth, and glossy.

Step 4: Stir in the Vanilla

Add the vanilla to the hot sauce and stir well. Adding it after heating protects its flavor, so you get a rounder, warmer taste. Your kitchen will already smell amazing at this point.

Step 5: Coat the Potatoes

Add the diced sweet potatoes to the bowl and stir until every cube is coated. Take your time here, because the sauce is your only seasoning. Evenly coated pieces cook up sweeter and more flavorful.

Step 6: Cook Until Fork-Tender

Pour everything into the slow cooker and cover it with the lid. Cook on High for 3 1/2 to 4 hours, or until a fork slides in easily. Then switch to the Warm setting until you are ready to serve.

Step 7: Top with Marshmallows

Stir the potatoes gently, then scatter the mini marshmallows over the top. Put the lid back on for 1 to 2 minutes, just until they soften and melt slightly. Serve right away while the topping is soft and sticky.

Additional Tips for Making This Recipe Better

These small habits made a big difference when I made this dish again and again.

• I always buy pre-diced sweet potatoes when I’m short on time, and the casserole turns out just as good.
• I check the potatoes at the 3 1/2-hour mark, because every slow cooker runs a little differently.
• I love a toasty top, so I sometimes move the cooked potatoes to a greased 13×9-inch ovenproof dish. I add the marshmallows and bake at 350°F for 3 to 5 minutes until they just begin to brown.
• If I want a softer, mashed texture, I mash the potatoes lightly before adding the marshmallows. I stop as soon as they are blended, because overmixing makes them gluey.
• I take the slow cooker to parties with the cooked potatoes inside, set it to Warm, and add the marshmallows right before serving.
• I use the slow cooker as a second oven during the holidays. Potatoes cool down fast, so it keeps them hot beautifully.

Common Mistakes to Avoid

I have made a few of these slip-ups myself, so learn from my kitchen.

• Skipping the cooking spray: I once scrubbed burnt sugar for ages. Spray the crock first and cleanup is easy.
• Cutting uneven cubes: Mixed sizes cook unevenly, and I ended up with mushy bits and hard bits. Aim for 1/2-inch pieces.
• Adding marshmallows too early: I did this once and got a sticky, melted mess. Add them in the last minute or two only.
• Using canned sweet potatoes: I tried it, and the texture was soft and the flavor too sweet. Fresh sweet potatoes keep their shape and taste better.
• Lifting the lid too often: Every peek lets heat escape and adds cooking time. I keep the lid on until the last hour.

How to Serve Slow Cooker Sweet Potato Casserole?

This dish belongs on any holiday table, but it works for cozy weeknight dinners too. A little presentation goes a long way.

• Serve it straight from the slow cooker set on Warm so guests can help themselves.
• Spoon it into a pretty serving dish and top with extra marshmallows for a soft, snowy look.
• Garnish with chopped pecans and a drizzle of maple syrup for crunch and shine.
• Add a tiny sprinkle of cinnamon on top for color and aroma.
• Pair it with roast turkey, ham, or roasted chicken and green beans for a colorful plate.
• Use half-cup scoops so every guest gets a neat, rounded portion.

Variations

Once you master the base recipe, it is fun to play with it. Here are a few ideas I like.

• Pecan topping: Sprinkle chopped pecans over the top for a crockpot sweet potato casserole with pecan topping.
• Dairy-free: Swap the butter for a plant-based butter, and check that your marshmallows suit your diet.
• Lower sugar: Cut the brown sugar a little, or use a brown sugar substitute. Taste before you add the marshmallows.
• Healthier lean: Skip the marshmallows and finish with toasted nuts for a lighter, healthy slow cooker sweet potato casserole.
• Extra warm spice: If you don’t have pumpkin pie spice, use 1/2 teaspoon each of cinnamon, nutmeg, and allspice.
• Mashed style: Mash the cooked potatoes lightly for a creamier, more traditional casserole texture.

Nutritional Information

Here is a quick look at what you get in each serving. The numbers below are for one 1/2-cup portion, based on 14 servings.

• Calories: 190
• Protein: 2 g
• Carbohydrates: 41 g
• Fat: 2 g

Make Ahead and Storage

This casserole is friendly to busy schedules. Use these guidelines to keep it fresh and tasty.

Make Ahead

You can prep this dish the night before. Cube the sweet potatoes and toss them in the sauce, then store them in a zip-top bag in the fridge. The next day, pour them into the slow cooker and start cooking.

Refrigerator

Store leftovers in an airtight container in the fridge. They stay fresh for up to 3 days. Keep the lid sealed tight so the casserole doesn’t pick up other fridge smells.

Freezing

I don’t recommend freezing this casserole. It doesn’t thaw and reheat well, and the texture suffers. It is better to make a smaller batch and enjoy it within a few days.

Reheating

Microwave single servings for 1 to 2 minutes until heated through. Then add a few fresh marshmallows on top. The leftover heat melts them perfectly.

Why You’ll Love This Recipe?

This dish earns its spot at the table for good reasons. Here is why it has become my go-to side.

• It saves oven space: The slow cooker handles the work, so your oven stays free for the turkey and pies. This matters most on busy holiday mornings.
• It is truly easy: You need only eight ingredients and about 20 minutes of prep. After that, the slow cooker does the work for you.
• It tastes like tradition: You get the sweet, spiced flavor and gooey marshmallow top everyone remembers. It feels classic without the fuss.
• It travels well: Cook it at home, then carry the whole slow cooker to the party. Set it to Warm and add the marshmallows right before serving.
• It is easy to customize: Add pecans, change the spice, or go dairy-free with a simple swap. The base recipe adapts to almost any table.

FAQs

Can I prep sweet potato casserole the night before?

Yes. Cube the potatoes, coat them in the sauce, and store them in the fridge in a zip-top bag. Pour them into the slow cooker the next day.

Can I make this recipe for a large crowd?

Yes. The 5-quart slow cooker has plenty of room, so you can double the recipe for more guests.

What if I don’t have pumpkin pie spice?

Use 1/2 teaspoon each of cinnamon, nutmeg, and allspice instead. It gives you the same cozy flavor.

Can I use canned yams or canned sweet potatoes?

I don’t recommend it. Canned ones are already cooked and often sweetened, and their texture is very different from fresh cubes.

Can I freeze leftover sweet potato casserole?

I wouldn’t. It doesn’t thaw and reheat well, so keep it in the fridge for up to 3 days instead.