Sunday, March 31, 2013

Sponge Cake with Rhubarb-Strawberry Compote

I came across this recipe in an insert in the San Francisco Chronicle and thought it a perfect dessert for a dinner we gave for some friends last week as
1. it contains no gluten, which one of our guests avoids
2. I'd never made either a sponge or angel food cake and wanted to try one
3. it relies on produce just coming into season

The potato starch substituted perfectly for flour in the dry ingredients, the compote was extremely easy to make and was a delicious accompaniment to the cake.

As this was my first sponge/angel food cake, I stayed faithful to the ingredients and directions as published in order to get the idea of the general techniques used.

'tis Spring! rhubarb and strawberries

in the saucepan with sugar and water

doesn't take long to get a nice syrup

potato starch sifted with a pinch of salt

yolks

whites

sugar - equal amounts each for the yolks and the whites

citrus juice with vanilla and almond extracts

orange and lemon zest

yolks beaten with sugar

wet batter after adding the zest

whites beaten to soft peaks

then to stiff with the sugar

egg whites ready for folding into the yolk batter

folding the starch into the batter

final smoothing before baking

Yeah I thought this look weird too but it's apparently how you cool a sponge cake

just prior to serving

Ingredients:
Rhubarb-Strawberry Compote:
1 pound rhubarb, trimmed and cut into 2-inch pieces
1 pint strawberries, hulled and sliced
2/3 to 1 cup sugar, depending on sweetness of fruit
1/2 teaspoon pure vanilla

Sponge Cake:
3/4 cup + 2 tablespoons (5 ounces) potato starch
1/4 teaspoon salt
7 large eggs, separated to yolks and whites
1 1/4 cups sugar, divided
1 tablespoon fresh orange juice
1 tablespoon fresh lemon juice
1 teaspoon pure vanilla
1/4 teaspoon pure almond extract
2 tablespoons finely grated orange zest
1 tablespoon finely grated lemon zest


Directions:
Rhubarb-Strawberry Compote:
Although many cooks do, I didn't string or peel the rhubarb at all and it came out fine. Whatever you do, though, just use the stalks as the leaves are quite poisonous!
Combine rhubarb, strawberries, sugar and 3 tablespoons water in a saucepan. Bring to a simmer over medium-low heat. Cook for 5-10 minutes, stirring occasionally until fruit begins to soften but still holds its shape, and juices become syrupy. Transfer to a bowl. Let cool. Stir in vanilla. Serve at room temperature or chilled. Keeps well in a covered container in the refrigerator for up to 3 days.

Sponge Cake:
Place a rack in the middle of the oven and preheat oven to 350°.
Set nearby an ungreased 10 x 3-inch round tube pan, preferably with a removable bottom. Place a long-necked bottle or a large metal funnel nearby for inverting the baked cake.
Sift the potato starch and salt onto a piece of waxed paper; set aside. I think the reason the recipe called for waxed paper as opposed to just sifting into a bowl was that the starch can be pretty sticky and harder to remove.

Separate the eggs, placing the whites in a bowl of a stand mixer and the yolks in a deep 1 1/2-quart bowl; set the bowl of egg whites aside. I'm not quite sure why they specify a hand mixer for the yolks and a stand mixer for the whites other than it was a way to avoid having use one or the other for both which would necessitate an extra cleaning between uses.

Using a hand-held electric mixer, whip the yolks on medium speed until thick and fluffy, about 2 minutes. Gradually add 1/2 cup plus 2 tablespoons of the sugar and continue whipping until the yolks are thick and pale yellow in color, about 2 minutes. Reduce to medium-low speed, add the orange and lemon juice, vanilla and almond extract and whip for another minute.

Carefully fold in the potato starch until no white shows and the mixture is smooth. Toward the end, fold in the citrus zests.

Attach the whisk attachment to the stand mixer and beat the egg whites on medium speed until the whites form soft peaks. Increase the speed to medium-high while gradually adding the remaining sugar until thick, shiny white peaks form that are stiff yet moist and bend softly on top. Fold about 1 cup of the whites into the yolk mixture. Now fold the mixture carefully into the whipped whites. Don't overmix. Gently pour the batter into the ungreased pan and smooth the surface.

Bake 50-60 minutes. When done, the cake should be golden-colored on top and feel spongy, springing back slightly upon being lightly touched. A round wooden toothpick inserted in the center should come out free of cake. If in doubt, baking 5 minutes longer won't harm the cake. 50 minutes was plenty of time in my case.

Remove the pan from the oven, and immediately turn it upside down over the long-necked bottle or funnel, inserted through the tube. It's fine if the pan tilts slightly. Let cake hang until completely cool, about 2 hours; then turn the pan right side up, and place it on the counter. Though the cake is cool to the touch, let it sit for at least 1 hour longer to cool the inside completely.

To remove the cake from the pan and maintain its shape perfectly, carefully slip a thin, flexible metal spatula down the side of the pan. Slowly trace around the perimeter to release the cake. When the sides are free, push up on the removable bottom of the pan to remove the cake. Tilt the cake and gently tap the bottom of the pan against the counter to loosen the cake, rotating as you do so, until the cake appears free. Cover the cake with a plate, invert the cake, and gently remove the bottom tube part of the pan. Cool completely.

To serve: Slice with a serrated knife, using a sawing action. Spoon the rhubarb-strawberry sauce alongside each slice.