Banana-Chocolate Sponge Cake
(for Passover or those on wheat-free diets)
This cake uses no chemical leavening and no everyday, regular
wheat flour, both being forbidden to those celebrating Passover.
It is a fine-textured, very tall sponge cake, with a distinct
taste of bananas underlying its chocolate flavor; leavening
is provided by air beaten into both egg yolks and egg whites.
You will note that the recipe uses dark rum, but that can be
omitted if you wish. Please note that I use unsweetened Dutch
process cocoa powder to make this cake; I have not tried to
make it with nonalkalized unsweetened cocoa powder, and I don't
know if that will work here. The finished cake will remain moist
for a couple of days at room temperature (if stored airtight);
it can also be frozen, though I think freezing dries it out
You'll need a 10" by 4" two-piece tube pan (the bottom and tube
will be in one piece, and the sides will be one piece). Do not
grease or line the pan! You'll also need a sturdy, long-necked
bottle for after the cake is baked. Foam-type cakes are very
delicate, and they must hang suspended and upside down to cool
completely before they are removed from the pan. Yes, it does
sound crazy, but I know that it works. I make this cake with
two mixers; a stand mixer (fitted with a whisk beater) for beating
the egg whites, and a powerful, hand-held electric mixer for
beating the yolks. If you wish, you can beat the yolks, then
wash and dry the same beater thoroughly and use it for the whites,
but be aware that if any grease is left on the beater, the whites
will not whip properly.
- 8 eggs,
graded "large", plus 1 egg white from an egg graded "large"
cups sifted or strained granulated sugar, divided
- 3/4 cup
plus 2 Tbsp. sifted potato starch
- 2/3 cup
sifted unsweetened Dutch process cocoa powder
- 1 tsp.
- 1/4 cup
tasteless vegetable oil
- 3 small
ripe bananas (to make one cup, pureed)
- 1/4 cup
- 2 Tbsp.
- 1 tsp.
freshly-squeezed, strained lemon juice
Adjust rack to one-third up from oven bottom. Have ready an
assembled, two-piece, 10" by 4" tube pan. Have ready a baking
sheet to place under the tube pan as the cake bakes.
Separate eggs (it's easiest to do this while they're still refrigerator-cold).
Place the yolks in a bowl of about three-quart capacity (or
the small bowl of an electric stand mixer). Place the whites
in the large bowl of an electric mixer, which must be perfectly
grease-free and of at least a 4-1/2 quart capacity. Cover both
bowls and leave the whites and yolks to warm up to room temperature
(about an hour).
Meanwhile, divide sugar by measuring out 1/2 cup; place near
bowl of egg yolks. Measure out remaining 1 cup and place near
bowl of egg whites. Into a medium bowl, sift together the potato
starch and unsweetened cocoa powder. With a fork, blend well,
trying to get out as many lumps as possible (potato starch tends
to clump--don't worry too much about it). Assemble other ingredients
and a food processor (fitted with steel blade).
When whites and yolks are about at room temperature, preheat
oven to 350 degrees F. With powerful, hand-held electric mixer
(or in small bowl of electric mixer fitted with whisk beater),
beat egg yolks at low speed to combine. Increase speed to high;
beat for 3 full minutes, or untol yolks are pale and have increased
slightly in volume. At low speed, add vanilla, then gradually
incorporate 1/2 cup sugar. When sugar has been added, scrape
bottom and sides of bowl with rubber spatula; increase speed
to high again and beat for 2 full minutes. Add oil, but do not
mix in. Working quickly, peel bananas and cut off any brown
or soft spots. Slice, then process in food processor at high
speed just until smooth. Measure out 1 cup of puree and add
to egg yolk mixture (note: bananas can be mashed with a fork,
put through a potato ricer, etc. instead of being put into a
food procesor, but the resulting puree should be smooth--not
chunky--and you'll need 1 cup of it). At medium speed, beat
in oil and banana puree just until combined. At lowest speed,
add about one-third of sifted dry ingredients and half of water;
beat just until combined. Scrape bottom and sides of bowl with
rubber spatula. Add half of remaining dry ingredients and all
of remaining water; beat at low speed till mixed. Add remaining
dry ingredients and rum, and beat at low speed just until combined
(this mixture will be thick).
To bowl of egg whites, add salt and lemon juice. With clean
whisk beater(s), beat at high speed until increased in volume
and very foamy. Decrease speed to low; add about 2 Tbsp. of
the 1 cup of sugar. Increase speed to high to incorporate sugar
thoroughly. Repeat this process, decreasing mixer speed to add
sugar, then increasing speed to high to incorporate each addition,
until all sugar has been added, beating for about 15 seconds
between each addition. When all sugar is incorporated, beat
meringue at high speed just until stiff peaks form. Remove from
Using a large rubber spatula, stir a large spoonful of the meringue
into the chocolate batter to lighten it. Add another large spoonful
of meringue and gently fold it in (not too thoroughly). Add
about one-third of remaining meringue; again, gently fold in,
not too thoroughly. Pour this lightened choclate batter gently
over the remaining meringue, and gently, carefully, and quickly
fold the two mixtures together just until all is combined and
no white streaks show. Turn into pan, which will be 2/3 to 3/4
full. Place pan on baking sheet, then immediately place in preheated
Bake 45 to 55 minutes. While cake bakes, get the long-necked
bottle ready. I turn the baking sheet back-to-front once, very
gently, after about 35 minutes of baking, but I don't open the
oven door before that. This cake will rise above the top of
the pan and develop deep cracks in its top surface (they won't
show when you serve it). Cake is done when top springs back
after being touched. Do not overbake.
Immediately after cake is removed from oven, gently turn it
upside down so that it is suspended on the neck of the bottle.
Be careful!! The cake pan will probably hang at a slight angle,
and it should be about a foot off the table to allow for air
circulation (I place my bottle on a cooling rack, which elevates
the cake a bit more). Cool cake in a draft-free area; it will
shrink a bit in volume while cooling. Allow to cool completely
before removing from pan; this may take as long as several hours.
When cake is completely cooled, carefully turn the pan right
side up (a bit of liquid may have exuded from the cake onto
the bottle--OK). To turn the cake out of the pan, loosen it
from the sides first, using a stiff, thin-bladed spatula, preferably
one made of plastic so it won't scratch your pan. Do not use
a sawing motion in doing this. Once the sides are loosened,
lift up the tube piece, and the cake should come with it. Now,
loosen the cake from the pan bottom with the same spatula. Carefully
and gently invert the cooled cake onto a large serving plate.
Serve the cake now, store airtight at room temperature for a
day or two, or freeze for longer storage. Just before serving,
sift a light dusting of confectioners' sugar onto the top and
sides of the cake. Cut with a large, sharp, serrated knife,
using a gentle sawing motion so you do not squash this delicate
12 to 16 servings
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