Thursday, October 31, 2013

Sweet Potato Cupcakes with Toasted Marshmallow Frosting

"Fall has always been my favorite season. The time when everything bursts with its last beauty, as if nature had been saving up all year for the grand finale.”
 -Lauren DeStefano - Wither

It's fall! Thanksgiving will be here before we know it. Where does the time go?

My mashed sweet potatoes
As a child, one of my favorite foods at Thanksgiving was the sweet potato casserole. You know the kind. Mashed up sweet potatoes loaded with brown sugar and butter, smothered with those little marshmallows.

My dry ingredients on the right, waiting to be mixed with in with everything else.

These cupcakes are my homage to that classic dish.

Before going in the oven - I used mini panettone cups instead of cupcake cups, whatever cups you use, greaseproof is best.

Moist and fluffy cupcakes are loaded with sweet potatoes, filled with yummy, warm, fall spices. The cake tastes like a cross between pumpkin cake and spice cake. The sweet potatoes in the cupcakes aren't used just for flavor, they happen to add to the cakes lightness and moisture level. White potatoes are often used to give baked goods these qualities. I even made a delicious Chocolate Farmhouse Cake that is filled with white potatoes.

The frosting recipe calls for cream of tartar, it helps the meringue become meringue. If you can't find it, it's o.k. to leave it out.
The frosting is a fluffy, light and sticky marshmallow frosting, that is broiled for a toasty marshmallow flavor. This kind of frosting is sometimes called a 7 minute frosting.

To make the frosting you need to have the bowl of your stand mixer sit over a saucepan filled with a few inches of water.

Seven minute frosting gets it's name because it takes about 7 minutes to whip egg whites into meringue, basically what the frosting is. I really like this frosting. It's actually something I use often since I always have the ingredients on hand, basically just egg whites, sugar and vanilla.


I used my handy point and shoot thermometer to make sure I got my mixture to the correct temperature, you don't need a thermometer for this recipe, you just cook it until it's hot. But I love using this thing, I highly recommend getting one if you do a lot of cooking. It's a breeze to take the temperature when making a caramel, or when frying to get the oil to the correct temperature.

I also like it because it can be whipped up quickly, and it compliments most cake recipes.

Beat the meringue until glossy, stiff peaks form - Note - this picture is showing a half recipe of frosting, a full recipe will fill the bowl.

It doesn't need to be toasted, but for this recipe, I highly recommend it. The toasted sticky marshmallow frosting and this cupcake just go amazingly together.

You don't even really need to toast these if you don't want to. If you leave them as is, they will be a fluffy marshmallow frosting or sometimes called a 7 minute frosting, because it takes about 7 minutes to beat.

These would sure compliment a Thanksgiving dessert table nicely. The classic combination of nostalgic flavors will make your guests smile.

Nice and toasty right from the oven.

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Beige vintage fall leaves tablecloth, Anchor Hocking amber cake stand circa 1960, Paragon "Melanie Rose"fine china vintage plates, tan damask vintage dinner napkins, Fenton Silver Crest milk glass candle holders, and Noritake M "The Vitry" teacups circa 1918, available at my Etsy shop, House of Lucien.

Take 20% off anything at House of Lucien by using coupon code, ALCHEMY at checkout!

Sweet Potato Cupcakes with Toasted
Marshmallow Frosting

Makes about 24 cupcakes

An original recipe by me, Melissa aka The Alchemist

** Note** These cupcakes after being frosted need to be served the same day. This type of frosting doesn't keep well. Serving them within a 3-4 hours is best, so plan accordingly. The cupcakes, unfrosted can last longer, as I noted below in the recipe.

Also you may need to double the frosting recipe to get as much frosting as I have on each cupcake. But! You can only make one batch at a time, because that is how much frosting can fit in the bowl of a stand mixer. Just be prepared and know you may need to make a second batch. If you use less frosting this amount may be enough.

Ingredients for Cupcakes

32 oz. sweet potatoes or yams (to equal 2 cups (536 g.) mashed after cooking)

2 3/4 cups (377 g.) all purpose flour

4 tsp. ground cinnamon

2 tsp. ground ginger

1/4 tsp. ground cloves

1 tsp. ground allspice

1/2 tsp. freshly ground nutmeg

1 tsp. baking powder

1 tsp. baking soda

1/2 tsp. salt

1 cup (190 g.) white sugar

1 cup packed (185 g.) brown sugar

1 cup (237 ml) vegetable oil

1 cup (216 g.) yogurt - I used Greek yogurt, full fat or low fat is fine, don't use nonfat

4 eggs

3 tsp. vanilla extract

Ingredients for Frosting

10 large egg whites

2 cups (380 g.) white granulated sugar

1/2 tsp. cream of tartar - This helps with the stability and volume of meringue, if you don't have this, or can't find it, it's o.k. to leave it out, but I do recommend it, especially if you are new to making a meringue.

1/8 tsp. salt

2 tsp. vanilla extract

Directions for Cupcakes

First cook the sweet potatoes. You can do this step a day or up to 3 days in advance. Preheat the oven to 400 degrees Fahrenheit, 200 degrees Celsius, or Gas Mark 6. Wash and scrub the sweet potatoes and pierce them a few times with a fork or a knife. Bake them in the preheated oven until they are soft, about 1 hour. Alternately, you can cook them in the microwave. Wash them and pierce them, and cook them for 8-10 minutes or until tender, turning them over once during cooking. Let them cool, then peel and mash them to equal 2 cups mashed or 536 g.

Start on the cupcakes - Preheat the oven to 350 degrees Fahrenheit, 180 degrees Celsius, Gas Mark 4.

In a large bowl, whisk together the dry ingredients, the flour, cinnamon, ginger, cloves, allspice, nutmeg, baking powder, baking soda and salt. Set aside.

In the bowl of a stand mixer, or in another large bowl with a hand mixer, mix together the 2 cups of mashed sweet potatoes, the oil and the white sugar and brown sugar, beat it until smooth. Add the eggs, one at a time, beating in between each addition. Scrape down the bowl and add the vanilla and the yogurt and beat it until everything is incorporated. Add the dry ingredients and beat until it is mixed together well, without over beating.

Fill cupcake cups 2/3 - 3/4 of the way full. I used miniature panettone cups I bought at Sur La Table. Whatever type you use, the greaseless cupcake liners are best, since all of my recipes have a high liquid and high oil content, if you use regular cupcake papers they may be greasy or oily on the bottoms, if you use the greaseless kind, that becomes a non issue.

Bake for 22-28 minutes, or until a toothpick comes out clean.

Cool the cupcakes before frosting them.

Cupcakes can be stored unfrosted for 2 days in an airtight container in the fridge. Or freeze them by wrapping them in plastic wrap then placed in a ziptop bag that is airtight. They can be frozen for 6 months at least, if wrapped well.

Directions for Frosting

Place the broiler on your oven on high and arrange a rack in the middle of the oven. Or alternately, you can use a kitchen torch, if you are using a torch, obviously don't preheat your broiler.

Fill a medium saucepan with a few inches of water and bring to a simmer. The saucepan needs to be a size that hold the bowl of your stand mixer on top of it, like a double boiler. (I have this pictured above.) When it starts to boil turn it down to medium. Put the egg whites, sugar, cream of tartar and salt in a clean bowl (the bowl needs to be very clean, there can't be any bit of grease in it or your meringue won't work) of a stand mixer and whisk by hand to combine. Place the bowl over the saucepan (make sure the water doesn't touch the bowl) and cook, whisking constantly until the sugar has dissolved and it is hot to the touch (about 120 degrees Fahrenheit, 48 degrees Celsius) on an instant read thermometer, about 5 minutes.

Transfer the bowl to the stand mixer fitted with the whisk attachment. Beat on medium for 2 minutes then turn up the mixer to medium high and beat until stiff, glossy peaks form, about 5 minutes more. You need to beat it on medium first, if you were to just beat it on high for the entire time the meringue can become dry, so it's best to gradually bring it up to the medium high speed and not just beat it on high the entire time. Add the vanilla and whisk until it's incorporated.

Transfer the frosting to a piping bag fitted with a large star tip. Pipe the frosting on the cupcakes.

Broil the tops to make them toasted. If using a kitchen torch, torch the tops until they are slightly brown and toasted. If using the oven, place the frosted cupcakes onto a cookie sheet or jelly roll pan. Place it on the middle rack of the oven. Broil them for 20-30 seconds, or just until they get brown and toasty. *** THIS IS IMPORTANT*** These can go from being done to burnt in what seems like a second. so don't walk away. Just stand there, even if you hold open the door to the oven slightly, to see what's going on, or you can set a timer for 20 seconds, then check them and see if they are toasted. Toast them until the tops are toasted lightly. It's better to keep checking them, than having them burn and have to start over.

Serve them within 3-4 hours of making them. If you must store a few cupcakes overnight, do so at room temperature in an airtight container. The trouble with storing them is, if you trap a moist cupcake in an airtight environment it's going to make the meringue which needs to be kept dry, wet. So overnight or the next day, the meringue will start to "sweat" or weep, get moist and start to fall off the cupcakes. Or if you were to keep them out in the open with air circulation, the cupcakes will dry out.

I hope you love this recipe as much as I do! Happy Baking!


papillon said...

How long does this frosting hold up in high temps?

Unknown said...

I'd love for you to add this to my link up party "Friday Follow Along Party"

Unknown said...

Wow your sweet potato cupcakes look awesome. Thank you for sharing this.

The Alchemist said...

Papillon - I'm guessing you mean sitting out at a high room temperature. If so, yes, they should hold up well in a hot climate, at least for a few hours.

Call Me PMc said...

These cupcakes look so good! Pinned to my Marvelous Mondays board, thanks for joining us at the party!

Carrie Robinson said...

These cupcakes are gorgeous! Forget sweet potato casserole! I want a cupcake. ;)
Thanks for sharing at Marvelous Mondays this week. Pinned & sharing!

Unknown said...

Has anyone tried this as a cake instead of cupcakes? If so, how was it and what, if any, adjustments did you make?

Mary said...

I love your sweet potato cupcakes! I featured you this week. Have a blessed weekend! Mary

The Alchemist said...

Paula Nelson - Sorry for the late reply, yes you can make this into a cake. It should make either a 2 layer cake in an 8 or 9 inch, or you can turn it into a bundt cake with a glaze instead of this frosting. Or use this frosting, that would be o.k. too.

If making cake layers I would grease the pans as well as cover the bottoms in parchment then grease the parchment, for easy removal of the cakes. If making a bundt, just make sure to grease the pan well, then flour it.

Happy baking!

Unknown said...

Your are alway a Class Act Lady!! I just love seeing how you display your treats! I just feel like I should buy one of the lovely Kentucky Derby hats and join you for tea:)

Hugs my sweet friend!!