Pumpkin Spice Cake Bars with Vanilla Buttercream Frosting (One-Bowl Recipe!)

These Pumpkin Spice Cake Bars with Creamy Vanilla Buttercream are the perfect fall dessert! Incredibly moist, perfectly spiced, and easy to make—no mixer needed. Chill before serving for the best flavor!

These are the best pumpkin bars I’ve ever had!

We had fall break last week, and my little baking buddy kept asking to make desserts. We baked frosted sugar cookies, banana bars, and these pumpkin spice cake bars with vanilla buttercream frosting. We actually had to make them twice because we had company stop by—and they went so fast!

These ARE the best pumpkin cake bars I’ve ever had. What I love most is that you only need one big bowl—no electric mixer or fancy equipment required. I used to make this recipe for my markets, and also in the shape of pumpkin loafs and muffins. Every fall, they would be the first to go next to the frosted sourdough cinnamon rolls at the farmers market.

I can’t wait for you to try this recipe. It only takes about ten minutes to mix together and thirty minutes to bake!

I plan to make these for Thanksgiving—and honestly, all throughout the fall season. If you’re looking for the perfect fall baking dessert, these pumpkin spice cake bars are it! It comes together in no time, tastes even better chilled, and will have your friends and family begging for the recipe!

These pumpkin cake bars are incredibly moist, melt-in-your-mouth, and send a wave of nostalgia through you with every bite. The spices remind me so much of growing up in the Midwest—windows open, the house filled with the scent of fall candles, and my mom’s cozy autumn décor all around. I think that’s one of the reasons I love this season so much—it brings back those comforting memories I always find myself craving as I get older. I hope one day the smells of baking and pumpkin spice will bring my kids that same nostalgic feeling.

I’m so happy to finally be feeling better—just in time for fall baking season! I hope you’re ready for more recipes to come because I have a lot to catch up on.

I currently have these pumpkin cake bars stored in a closed container in the fridge—and let’s just say, the door is being opened way too often because I can’t resist them. Baking these while pregnant might not have been my best decision, but you know what? Who cares—they’re absolutely worth it!

One of the reasons I love this recipe so much is that it’s made with simple, everyday ingredients you probably already have hiding in your pantry.

Pumpkin Spice Cake Bar Ingredients:

Canned pumpkin purée
Eggs
Sugar
Brown sugar
Butter (melted or softened)
Vanilla extract
All-purpose flour
Baking soda
Baking powder
Sea salt
Pumpkin pie spice
Ground ginger
Ground allspice
Ground cinnamon
Ground cloves

Powdered Sugar
Milk
Vanilla
Butter

How to Make The Best Pumpkin Cake Bars:

Step One:
Preheat the oven to 350°F. In a large mixing bowl, whisk the eggs until well beaten. Add the pumpkin purée, sugar, brown sugar, vanilla, and butter, then slowly pour in the melted butter while mixing until fully combined.

Step Two:
In a separate bowl, sift together the flour, baking powder, baking soda, sea salt, pumpkin pie spice, allspice, cinnamon, cloves, and ginger.

Step Three:
Gradually add the dry ingredients to the wet mixture, stirring until everything is well incorporated and smooth.

Step Four:
Line a 9×13-inch glass baking dish with parchment paper (I like to spray both the parchment paper and edges of the dish with cooking spray). Evenly pour the batter into the prepared dish.

Step Five:
Bake for 30–35 minutes, or until a toothpick inserted in the center comes out clean. Be careful not to overbake—the cake will continue to cook slightly as it cools. Let it cool completely before spreading on the vanilla buttercream.

How to Make Vanilla Buttercream Frosting (No Mixer Needed):

Step One:
Melt the butter in a small saucepan or microwave-safe bowl.

Step Two:
In a large mixing bowl, combine the powdered sugar, milk, vanilla, and melted butter. Mix well using a whisk or spatula until smooth and creamy.

**If the frosting is too runny, add a bit more powdered sugar until it thickens.
If it’s too thick, add a splash more milk until you reach your desired consistency.

Step Three:
Give it a quick taste test and adjust as needed—add a little more butter or vanilla if you’d like a richer flavor!

Step Four:
Once the bars are completely cooled, pour the vanilla buttercream frosting over the top and spread it evenly with a spatula. For a festive touch, add some cute fall sprinkles or a light dusting of cinnamon on top.

Step Five:
Place the bars in the refrigerator to chill before slicing. Trust me—these bars taste absolutely incredible when served cold! The frosting firms up perfectly, and the flavors blend together beautifully. They’re even better the next day as the spices have time to deepen and become more flavorful.

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How many slices does this pumpkin cake recipe make?

Depending on how large or small you slice them, you can cut the bars into 12 generous pieces or 16 medium-sized slices—perfect for sharing! I made 16 for my husband to take into work, and they were a hit. Or honestly, if it’s just for you, don’t even bother slicing—grab a fork and dig right in!

How to Store Pumpkin Spice Cake Bars

To keep your pumpkin spice cake bars fresh and moist, store them in an airtight container in the refrigerator for up to 5 days. I actually think they taste even better the next day once the spices have had time to deepen in flavor.

The BEST Pumpkin Bars you’ll ever have

You’re going to love these pumpkin cake bars because, even though it’s cake, they’re unbelievably gooey, ultra-moist, and packed with the ultimate cozy fall flavors in every bite.

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How to Make Pumpkin Spice Cake Bars Gluten-Free

You can easily make these pumpkin spice cake bars gluten-free! Simply replace the all-purpose flour with a 1:1 gluten-free flour blend—I recommend brands like Bob’s Red Mill 1:1 Baking Flour or King Arthur Measure for Measure. These blends already include xanthan gum, which helps the bars stay soft and moist. I also LOVE the Trader Joe’s gluten-free flour.

Everything else in the recipe is naturally gluten-free, including the frosting, so no other substitutions are needed. The bars will turn out just as delicious—gooey, spiced, and perfect for fall!

More of my FAVORITE fall recipes:

Pumpkin Spice Olive Oil Cake with Cream Cheese Icing
Cranberry Almond Cake
Healthy Apple Pie
Dark Chocolate Cranberry Cookies
Pumpkin Crinkle Cookies
Pumpkin Pie
Spiced Zucchini Bread
Orange Ginger Molasses Cookies

I hope you love these pumpkin bars as much as we do! We are on our way to make another batch today while the Eagles play!