Sweet potato cake with marshmallow topping

On October 1 I went to a nearby store on a butter run. When I walked in, there were pumpkins everywhere. There were fake spiders almost everywhere. The place looked so different, I was a little disoriented. Should I be wearing something different? Am I invited to whatever is happening here? Wait, what am I doing here again? Where’s the eggnog? If October 1 is the official beginning of the holiday decoration rush, I can sure deal with that. Frankly, I was relieved not to see anyone wearing reindeer ear headbands and jingle bells on satin strings around their necks just yet. I guess everyone is taking their time this year.The Halloween decorations reminded me that despite the heat that just won’t quit, it is fall. And since it’s fall, maybe I can help force the season a little bit and take care of my sweet tooth with my favorite, and only, sweet potato cake. Now even if you’re not a sweet potato fan, you are going to like, maybe even love, this cake. If I didn’t tell you it was sweet potato, I don’t think you’d be able to put your finger on just what was in this cake. If you are a sweet potato fan, then this will only deepen your connection to this vitamin A-packed powerhouse.


The only bummer in making this cake yesterday is that while it is fall, it’s still warm out, and I needed to bake a couple of sweet potatoes. So my oven was going at 450°, all the windows were open, and for a little over an hour, I felt guilty for my newest contribution to indulgent energy use. Once the sweet potatoes were cooled and peeled, I put them through the ricer and wondered like I always do when I use the ricer, why don’t I use the ricer more? But there was no time for these deep considerations. I had dry ingredients to whisk, and butter and sugar to fluff!


The batter turns out to be a beautiful orange before you mix the dry ingredients in.


And once you’ve mixed your dry ingredients in, you’ve got a thickthickthick batter that’s kind of tough to spread, but eventually gets done. Down below you see that the cake comes out of the oven not looking a whole lot different than when it went it. It gets a nice rise, and after 5 minutes of resting, you’re able to pop it out easily for the big cool down.

With the cake done, you can get the topping underway, brought to you by the magic of egg whites. The first time I made this cake, I didn’t have a kitchen torch yet. I just spread the topping all over the cake and added a bunch of dollops that held their shape. The torch, though, helped bring a whole new level of flavor: Toasted marshmallow. I can take or leave marshmallows (don’t judge!), but this stuff I just can’t pass up. I love it. How much? I love it enough to lick the whisk attachment nearly clean. I love it enough to do some bowl licking. It’s so, so good.


If you’re talented with piping, you could make a really cool cake top. I am one level below novice when it comes to piping, so I use my frosting spatula (which is really easy to lick the topping off of) and make waves on top. Sometimes I just dollop spoonfuls all over, letting them fall as they may. Follow your heart.


When you get your torch (you know you’re thinking about it), I wouldn’t bother with a “culinary torch” at all. Pop over to the hardware store and pick up a sturdy mini. I read through a lot of  reviews and a handful of articles comparing the kitchen torch with non-kitchen-specific torches before landing on this one.

Barely, barely adapted just from Smitten Kitchen’s sweet potato cake with marshmallow frosting

Ingredients (cake)

1.5 pounds sweet potatoes
250 grams all purpose flour (~2 cups)
1 3/4 teaspoons baking powder
1/2 teaspoon baking soda
1/2 teaspoon salt
1 teaspoon cinnamon
1/4 teaspoon ground ginger
1/4 teaspoon ground cloves
1 stick butter at room temperature (1/2 cup)
190 grams packed light brown sugar (~1 cup)
1/2 teaspoon vanilla
2 large eggs

Ingredients (topping)

3 large egg whites
3/4 cup granulated sugar
pinch of salt
1/4 teaspoon cream of tartar (you can substitute a 1.5 teaspoons of lemon juice if you don’t have cream of tartar. I haven’t tried this but have read this is a common, almost unnoticeable sub.)

How to (cake)

Bake  your sweet potatoes. At 450°, I baked my 2 sweet potatoes for a little over an hour (this included the preheating) before they were good and done. Bake them the way you’d usually bake potato or sweet potato. The original recipe lists a 375° temperature for 45 minutes to an hour. I tried that my first time making this cake and it didn’t work for me. I also have a crap oven which may account for some of that. You can take care of this step the same day or do it ahead of time. However you go about this, let your sweet potatoes cool completely before using them in your batter.

Once you’ve got your sweet potatoes sorted out, preheat your oven to 350° and line the bottom of an 8-inch square pan with parchment paper. Butter the sides of the pan. If you’re anxious about potential sticking, butter the paper, too.

Peel your sweet potatoes and put them through a ricer until you have 12-13 ounces of mash (approximately 1.5 cups).

Whisk flour, baking powder, baking soda, salt and spices until combined.

In a large bowl (this is going to be your main bowl), use an electric mixer to beat together your butter and brown sugar until they’re fluffy (about 3 minutes). beat in the vanilla and eggs until combined. Next, add the sweet potato puree and mix until combined. You are now done with your mixer.

Add your flour mixture and fold it in using a spoon or silicone scraper spatula. You are going to have some thick batter.

Spread your batter in your prepared pan and bake until a toothpick comes out clean from the center, 35-40 minutes.

Let the cake cool on a wire rack for 5 minutes before flipping it out onto another cooling rack and letting it cool completely. In a pinch for time (or a raging sugar jones) you can put the cake in the fridge or freezer for a bit to speed up the cooling. Set a timer in 5-minute increments if you use the freezer so you don’t freeze any part of the cake, which I’ve never ever done.

How to (topping)

Using a double boiler or a heatproof bowl over a small pot of simmering water, combine your eggwhites, granulated sugar, salt and cream of tartar. Whisk for 3 minutes until your egg whites are warmed and the sugar is all or at least mostly dissolved.

Put this mixture into the bowl of your stand mixer or get another big bowl and your electric mixer and whip it at high speed until you have stiff and glossy peaks (about 5 minutes, maybe a little more). Mix in vanilla just until combined.

Putting it together

First spread a thin layer of the toppping over the top of your cake. Fill a piping bag and go to town! OR…you can use a spoon or frosting spatula to spread the topping all over however you’d like. This is pretty fun to do with such a stiff medium. It’s like soft sculpture. I don’t ever end up using all of the topping, but that may be a flaw in my artistry.

Use your torch to brown the topping and get ready for a light toasted marshmallow smell to fill your kitchen. You’re a boss. Well done.

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