Monday, February 22, 2010

Pecan Sweet Potato Pound Cake

Baking American desserts in France involves a lot of obsessing on my part. Will I be able to find all the appropriate ingredients? Do I have the right equipment? Will the recipe work if I need to tweak it? Am I using the right kind of flour? Every time we go to a big store, not just the little "superette" here in town, I scour the shelves for specialty ingredients that I might need for one of the blog desserts. Right now my quest is for tapioca, but I suppose that can wait...
So the Pecan Sweet Potato Cake was a bit of a challenge for me. The pecans were not a problem, because I had imported a lot. The sweet potato turned out also to be less of a challenge than I had thought--many market vendors sell them here. I found a particular kind of coconut that is more like American sweetened coconut and less like the usual powdery unsweetened kind you get in France.

So here are all my carefully culled ingredients. Note that French sweet potatoes, like the African ones, are white rather than orange. I think they're also a bit less sweet. Not pictured here: the frosting ingredients.

Here's my pile of shredded sweet potato. Doesn't look too appetizing, does it? Fortunately, it baked up into a golden brown cake.

Oops, some of it stuck to the pan. I really should learn that you do actually have to grease a silicone pan. And note here that I made one big layer. This is supposed to be a three-layer cake, but I don't have three layer cake pans, so I made do. Sami was kind enough to split this horizontally for me so that we actually had two layers.

OK, this is my moment of glory. I was freaking out about how I would make the marshmallow frosting. I could not find any of these crucial ingredients/equipment: candy thermometer, corn syrup, cream of tartar. So I went on the Internet and did some research on 7-minute frosting, which this seemed to be, approximately. I looked here and here for the basic technique and then made it up as I went. I would have to go by time and texture rather than temperature, and I would somehow have to compensate for the lack of cream of tartar. Knowing that cream of tartar is an acid (I'm not sure where I picked that up), I squeezed the juice of half a lemon in with my egg whites, sugar, and a touch of water. Then I put my mixing bowl over a pot of simmering water, powered up the mixer, and set the timer for 5 minutes. You see the lovely results! I'm so proud.

Mmmm...cake with fluffy frosting and coconut. Does it remind you of something? Like the banana cake of a couple of months back?
This was good, but the banana cake was better. Julia, in her critique, said, "I don't see the point of the sweet potato in here. It's like a lot of these recipes, where she has you put weird ingredients in just to show you it can be done." Or something like that. An American sweet potato would probably give this more flavor, for sure. And I know that Alicia's towering three-layer delight will make my puny cake look very lame. But I'm not complaining. I got through the ingredient hurdle and the equipment hurdle and turned out a pretty darned good cake. The fact that there's only half a cake downstairs and we haven't had guests over (yet) speaks for something.

Here's the recipe. I'm going to give you the full Maida version with the candy thermometer, and then I'll try to recreate my half-assed 7-minute frosting.

Pecan Sweet Potato Pound Cake

1-1/2 c. (12 oz.) canola or salad oil (I used half melted butter)
Scant 2 c. (11 oz.) sugar
1 T. baking powder
1/4 t. salt
1 t. ginger
1 t. nutmeg
4 large eggs, separated
1/4 c. boiling water
1 t. vanilla
2-1/4 c. (9 oz.) sifted flour
1 lb. sweet potatoes, peeled and shredded FINE (use the small holes on your grater)
6 oz. toasted pecans, broken in pieces (or TJ's fabulous pecan pieces)

1/3 c. apricot jam, heated and strained
7 oz. shredded coconut

Heat the oven to 350 and get out 3 8-inch layer cake pans. Butter them, line them with parchment, and butter and flour them. In a large bowl, whisk together the oil, sugar, baking powder, salt, ginger, and nutmeg (you can use your electric mixer for this, but it's really not necessary). Add the egg yolks and beat to mix. Then add the boiling water and vanilla. Fold in the flour, and then add the sweet potatoes and pecans. Beat the egg whites until you get stiff peaks, then fold them into the batter in 2-3 batches. Divide the batter among the pans and bake for 30-35 minutes or until a toothpick comes out clean.
Let cool in the pans for about 3 minutes; turn out onto racks and let cool. While they're cooling, you can heat (microwave for about 30 seconds) and strain your jam.

Now it's time to make frosting. This is Maida's recipe, which I was unable to try. You need an accurate candy thermometer.

1-1/2 c. sugar
2/3 t. (?) cream of tartar
2/3 c. water
1/8 t. salt
5 oz. (about 5) egg whites; these can be frozen (thawed) leftover egg whites.
1 t. vanilla
1/4 t. almond extract

Put the sugar, cream of tartar, and water in a smallish saucepan over medium heat and stir until the sugar is dissolved. Cover it and let the mixture boil for 3 minutes. Then uncover and put in your candy thermometer. Let it boil without stirring until it reaches 242. While it's boiling, put your egg whites and salt in your stand mixing bowl with the whisk attachment. When the syrup reaches 236, turn on the mixer and start beating until the egg whites are stiff. Once the syrup reaches 242, keep the mixer on high and pour the syrup in a thin, steady stream over the egg whites. Keep beating for 5 minutes while the icing gets thick and stiff. Add the vanilla and almond extracts and beat another couple of minutes. OK, now get ready to ice the cake.
Put a cross-hatch of waxed paper strips on your cake plate and put layer one of cake on top of that. Spread a thin layer of jam on there, then give it a 1/2-inch layer of frosting. Put the next layer on top and repeat with the jam and icing. Once you get to the top layer, put the jam on top, but then Maida says to start with the sides and then frost the top. She's probably right. In any case, make your frosting all pretty and swirly, then get out your coconut and do your best to press coconut all over the sticky white frosting. If you're lucky like me, you'll end up with white frosting and coconut all over your hands, which you will then have to lick. Serve and enjoy your masterpiece.

Maria's Half-Assed Seven-Minute Frosting (for a small two-layer cake)

3 oz. egg whites
5 oz. sugar
Pinch salt
Juice of half a lemon
about 2 T. water
1/2 t. vanilla
Dash of almond extract

You'll need a heatproof (not plastic) mixing bowl, a saucepan that the bowl can sit over, and a hand mixer for this. Heat a few inches of water in the saucepan over medium heat. Put your egg whites, sugar, salt, lemon juice, and water in the mixing bowl. Set it over the hot water and immediately turn on the mixer to high. Set a timer for 5 minutes and keep beating. After the 5 minutes is up, take the bowl off the saucepan (careful, it's hot!), add the vanilla and almond, and continue to beat another 2 minutes. You should have a bowl full of fluffy white goodness. It crusts over pretty fast, so you'll want to frost your cake soon.

1 comment:

  1. Good memory on Cream of Tartar! it is potassium hydrogen tartrate, which is partially neutralized tartaric acid. White vinegar (acetic acid) works as well as lemon juice (citric acid).