Sweet Potato Muffins with Oat Streusel Topping

These Sweet Potato Muffins with Oat Streusel Topping are moist, spiced, and bakery-style delicious, with a crunchy oat topping that makes them irresistible.

Sweet Potato in Muffins? Are You Sure? 

Oh, yes, friends. I’m sure. I’m very, very sure. 

If you know me at all, you know I’m allergic to a lot of fall spices and most gourds (like pumpkin). So, the holidays are rough on me. Very rough. 

That said, I discovered a few years back that I could easily swap out mashed sweet potatoes for pumpkin puree. That realization has changed everything for me as a baker, especially during the fall season, when people are craving pumpkin spice everything. 

I love sweet potatoes. They’re sweet. They’ve got a lovely texture, and they bake up just like pumpkin. And you can doctor them with cinnamon, allspice, nutmeg, cloves, and so on, to get those rich holiday flavors.

So, you can bet your bottom dollar I plan to use them as often as I can. 

Why These Sweet Potato Muffins? 

I was baking another recipe and had a full cup of mashed sweet potatoes left over. I had a hankering for muffins. Like, the beautiful ones you see in a bakery. The kind with streusel on top. 

I’ve made other muffins in the past, of course. I’ve got a collection, including my Cinnamon Sugar Muffins, my Cranberry White Chocolate Muffins, and Double Dark Chocolate Espresso Muffins. (Yum!)

But this time?

Well, I’m pulling together all of my holiday posts right now and I decided to go with a spice cake base for my muffins. 

Yep, you read that right. These muffins, like to many of the bakes on my site, start with a box of cake mix. 

Is that cheating? I don’t care, honestly. They baked up so perfectly that I make zero apologies. Instead, I will await the emails from you after you’ve made these, because I’m that confident you will love them. 

Is it the mild spice of the cake merged with the sweet potatoes? Is it that crunchy streusel topping? 

Honestly, it’s all of the above, so let me just say right now. . .you’re welcome. 

Sweet Potato Muffin Ingredients

I’ve got an easy printable recipe card at the bottom of this recipe, so be sure to check that out. This is just a quick peek at what you’ll need. These are simple ingredients you’ll find at any grocery store. 

For the Muffins:

• 1 box spice cake mix (or yellow cake mix + 2 teaspoon pumpkin pie spice)
• 1 cup mashed sweet potatoes (cooked and cooled)
• ½ cup vegetable oil or melted butter
• 3 large eggs
• ½ cup sour cream (can replace part with milk if desired)
• 1 teaspoon cinnamon (optional, for extra spice)
• ½ teaspoon nutmeg (optional)

For the Oat Streusel Topping:

• ½ cup old-fashioned oats
• ½ cup light brown sugar, packed
• ½ cup all-purpose flour
• 1 teaspoon cinnamon
• ¼ cup unsalted butter, cold and cubed
• Optional: ¼ cup chopped pecans or walnuts

For the Pumpkin Spice Glaze (Optional):

• 1 cup powdered sugar
• 2–3 tablespoon milk or cream
• ½ teaspoon pumpkin pie spice
• ½ teaspoon vanilla extract

How to Make Sweet Potato Muffins with Streusel Topping

These come together so easily (as most cake mix recipes do) but they taste like you’ve slaved all day! 

Preheat oven to 350°F. Line a muffin tin with 18–20 liners.

In a large bowl, whisk together eggs, oil, sour cream, and mashed sweet potatoes until smooth.

Stir in the cake mix and spices until just combined (don’t overmix).

In a small bowl, prepare the streusel: combine oats, brown sugar, flour, and cinnamon. Cut in the butter with a fork or pastry cutter until crumbly. Stir in nuts if you're using any.

Divide muffin batter into liners, filling about ⅔ full.

Sprinkle each generously with streusel topping. Press down with your palm to adhere the topping to the batter.

Bake 18–22 minutes, or until a toothpick comes out clean.

Cool muffins slightly before serving.

Serve and enjoy!

Optional Glaze:

In a small bowl, whisk together powdered sugar, milk, pumpkin pie spice, and vanilla until smooth. Drizzle over cooled muffins. Let set for 10–15 minutes before serving.

What to Expect from These Muffins

If you’re looking for the perfect blend of spice, texture, and holiday pizazz, you’ve found it! The spice cake in this recipe is the perfect foundation for what turned out to be a terrific muffin.

I adored the streusel on top, especially the oats. But I suspect that even without the topping I still would have loved the muffins. They are what I would call “soft” spice, meaning they don’t punch you in the face. Instead, these are the kinds of muffins that you bite into and a smile immediately turns up the edges of your lips.

Don’t believe me? Well, bake up a batch and then we’ll talk. Until then, you’ll just have to take my word! I am currently dieting, which is a bummer, so I took these to a precious friend who’s going through a tough season. I knew they would cheer her up.

I also took a few slices of my Pumpkin Pound Cake, for good measure. Hey, when you’re blessing others, you go all out, right? That’s how we do things down here in Texas, anyway! 

Things to Love About These Muffins

• They’re moist and tender, thanks to sweet potatoes and sour cream.
• The buttery oat streusel gives them a bakery-style crunch.
• Pumpkin spice glaze adds an optional cozy, fall-inspired finish.
• Perfect for breakfast, brunch, or snacking with coffee or tea.
• A great way to use up leftover mashed sweet potatoes.

Variations on this Recipe

I can imagine all sorts of fun additions to these muffins. Here are a few ideas that come to mind: 

Pecans or Walnuts: Next time, I might add some finely chopped nuts to the streusel. 

Caramel or Butterscotch drizzle: This just sounds delicious to me! 

Butterscotch Chips: I was wishing I had some of these in my house to add to this recipes. I think they would be a lovely complement! 

Oats in the muffins: If you want to bulk these up, (say, for a breakfast treat) you might consider adding half a cup of oats to the batter. I think this would add a lovely texture. 

Really, the possibilities are endless, friends! 

Other Sweet Potato Favorites from Out of the Box Baking

If you liked these sweet potato muffins, you will probably enjoy the following: 

Sweet Potato Pound Cake: If you love the yummy goodness of sweet potatoes and those warm spices of fall you’re going to flip over this simple but delicious pound cake from Out of the Box Baking. 

Sweet Potato Pie Dump Cake: If fall had a flavor, this sweet potato pie dump cake would be it. Layers of velvety sweet potato filling are topped with a buttery cake mix crumble, baked until golden, and dusted with warm spices. It’s all the cozy comfort of a classic sweet potato pie with the ease of a dump-and-bake recipe—perfect for busy holiday kitchens.

Sweet Potato Pocket Pies: If you're a fan of sweet potato pie but you love a light, crisp puff pastry, this is the recipe for you! These simple pocket pies come together so easily and they taste delicious! 

Sweet Potato Casserole (two ways): Check out this delicious holiday side dish from my friends at Backyard Texas Grill. It’s delicious! 

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Thanks for stopping by, friends! If you make this recipe and enjoy it, let me know in the comments. In the meantime, go ahead and pin some photos to your Pinterest boards! 

About the Author

Hi! I’m Janice, the baker behind Out of the Box Baking. I love showing home bakers how to transform simple ingredients—like a boxed cake mix—into bakery-worthy treats. These sweet potato muffins are one of my favorite cozy fall bakes, perfect for breakfast or sharing with loved ones.