From the roundup: 24 Easy Fall Treats Recipes Your Family Will Actually Eat
Sweet potato marshmallow blondies came out of a Thanksgiving where I had leftover sweet potato puree and no room in the oven for another casserole dish. The whole thing comes together in about 20 minutes of actual work, and the oven does the rest. One 9×13 pan, 24 bars, done.
The batter is a brown butter blondie base with mashed sweet potato and warm spices folded in. It bakes for about 20 to 22 minutes until just set, then you scatter mini marshmallows over the top and give it another 8 to 10 minutes. That second bake is where the magic happens, but keep an eye on it because marshmallows go from toasted to scorched faster than you’d expect.
Total time is just under an hour, including baking, but you need to add at least another hour for cooling before you cut. I know that part is annoying. Skip it and the marshmallow layer will drag all over your knife and the bars will fall apart.
How this one actually started
I made these for the first time the Wednesday before Thanksgiving because I had opened a can of sweet potato puree for something else and only used half. I did not want to waste it, and I needed a dessert that could sit on the counter overnight without anyone touching it before the meal. These fit perfectly, and I actually sliced them the next morning before the chaos started.
My pickiest kid, who will not touch sweet potato casserole at the actual table, ate two of these without asking what was in them. I did not volunteer the information.
Why you will love this
- One pan makes 24 bars, which is enough for a holiday table or a school potluck without doubling anything
- Brown butter takes about 5 minutes and does a lot of the flavor heavy lifting so you are not relying on spices alone
- Canned sweet potato puree works perfectly here, no roasting or mashing required
- The bars actually slice more cleanly the next day, so this is a genuinely good make-ahead dessert
- No mixer needed, just a saucepan, a bowl, and a spatula
Tips for success
- Brown the butter until you see actual brown specks on the bottom of the pan and it smells nutty. Pale golden is not far enough. Those solids are where the flavor is.
- Let the butter and sugar mixture cool for a full 5 minutes before adding the eggs. I have scrambled eggs into blondie batter before. It is not a fun fix.
- Add the marshmallows only in the last 8 to 10 minutes of baking, not at the start. They burn quickly and will be a dark, sticky mess if they go in too early.
- Wipe your knife blade between every cut when slicing the cooled bars. Marshmallow is sticky and will drag and tear the top if you do not clean the blade.
Common questions about this recipe
- Can I use sweet potato pie filling? No. Pie filling is already sweetened and spiced, and it will throw off the texture and flavor balance of the batter. Use plain puree.
- My marshmallows browned unevenly. Is that okay? Yes. Oven hot spots cause this. As long as most of the marshmallows are puffed and lightly golden, the bars are done.
- Can I cut these warm? Not really. The marshmallow layer needs at least an hour to set at room temperature or it sticks badly to the knife and the bars lose their shape.
- Do these need to be refrigerated? Not for the first two days. After that, yes, move them to an airtight container in the fridge.
Substitutions
Canned sweet potato puree and homemade mashed sweet potato both work here. Just make sure it is plain, not pie filling. Butternut squash puree is a reasonable swap if that is what you have. For dairy-free, use a vegan butter stick in the same amount. The brown butter step still works, though the flavor will be slightly different.
If someone in your house does not like marshmallows, you can skip the topping entirely and just bake the blondies for the full 30 to 32 minutes. They are good on their own. Chopped pecans or walnuts folded into the batter before baking also add a nice texture if you want something in place of the marshmallow layer.
Make-ahead and storage
These are genuinely better the next day. Bake them the night before, let them cool completely, then cover the pan and leave it at room temperature. The marshmallow sets up firmer overnight and the bars cut cleanly in the morning. Store finished bars in an airtight container at room temperature for up to 2 days, or in the refrigerator for up to 5 days. Layer them between sheets of parchment so the marshmallow tops do not stick together.
To freeze, wrap individual bars tightly in plastic wrap and store in a freezer bag for up to 2 months. Thaw at room temperature for about an hour. The marshmallow texture softens a bit after freezing but the bars are still good.
Sweet Potato Marshmallow Blondies
Ingredients
Equipment
Method
- Preheat your oven to 350 degrees F. Grease a 9×13 inch baking pan with butter or nonstick spray, then line it with parchment paper leaving a little overhang on the long sides so you can lift the bars out cleanly.
- Brown the butter first. Melt it in a medium saucepan over medium heat, stirring occasionally. Keep cooking after it melts, about 4 to 5 minutes, until the butter turns a golden amber color and smells nutty. Small brown specks will form on the bottom of the pan. Pull it off the heat right away and pour it into your large mixing bowl so it stops cooking.
- Whisk the brown sugar into the hot browned butter until fully combined. Let it cool for 5 minutes so it does not scramble the eggs, then whisk in both eggs and the vanilla extract until the mixture looks smooth and slightly glossy.
- Stir in the sweet potato puree with a rubber spatula until no streaks remain. Add the flour, cinnamon, nutmeg, ginger, baking powder, and salt. Fold gently until just combined. A few small lumps are fine. Do not overmix or the blondies will be tough.
- Spread the batter evenly into the prepared pan. Bake for 20 to 22 minutes until the top looks set and a toothpick inserted in the center comes out with moist crumbs but no wet batter.
- Scatter the mini marshmallows evenly across the top of the blondies. Return the pan to the oven and bake for another 8 to 10 minutes until the marshmallows are puffed and golden brown on top. Watch them closely in the last few minutes as they go from golden to burned quickly.
- Remove from the oven and let the pan cool completely on a wire rack, at least 1 hour. The marshmallow layer needs to set before you cut. Use the parchment overhang to lift the slab onto a cutting board, then slice into 24 bars with a sharp knife. Wipe the blade between cuts to keep the marshmallow from dragging.
Notes
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