1. Position the oven rack in the lower third of
the oven. Preheat the oven to 450 degrees.
2. Dissolve
the cocoa in 3 tablespoons boiling water and cool.
3. Separate 2 of the eggs, placing the yolks in 1
large mixing bowl and the whites in another. To the yolks, add the additional
yolk, the 2 remaining eggs, and ½ cup sugar.
(If not using the syrup, increase the sugar to 2/3 cup plus 1 tablespoon.)
Beat on high speed 5 minutes or until thick, fluffy, and triple in volume. Add
dissolved cocoa to the beaten yolk mixture, beating a few seconds or until
incorporated.
4. Sift ½ the flour mixture over the egg mixture
and fold it in gently but rapidly with a large balloon whisk, slotted skimmer,
or rubber spatula until the flour has disappeared. Repeat with the remaining
flour mixture.
5. Beat the egg whites until foamy, add the cream
of tartar, and beat until soft peaks form when the beater is raised. Beat in the
remaining 1 tablespoon sugar and beat until stiff peaks form when the beater is
raised slowly. Fold the whites into the batter and pour into the prepared pan,
using an angled metal spatula to level it.
6. Bake for 7 minutes or until golden brown, a
cake tester comes out clean, and the cake is springy to the touch.
7. Loosen the edges with a small metal spatula or
sharp knife and, lifting by a long edge of the liner or parchment overhang,
gently slide the cake from the pan onto a flat surface. To use the biscuit for a
round cake base or cutouts, allow to cool flat, covered with a clean dish towel.
To use it for a roll, roll it up while still hot. If using a liner, tightly roll
up the biscuit with the liner. (This keeps the biscuit especially moist.) If
using parchment, flip the biscuit onto a clean dish towel, carefully remove the
parchment, and roll it up tightly, towel and all. Cool on a rack. When ready to
fill, unroll the biscuit. (If a liner was used, first detach the cake from liner
and then replace it on the liner.) If using the syrup, sprinkle it on the cake
before spreading it with 2 cups filling.
TO MAKE SYRUP:
In a small saucepan with a tight-fitting lid bring the sugar and water to a
rolling boil, stirring constantly. Cover immediately, remove from the heat, and
cool. Transfer to a liquid measuring cup and stir in the liqueur. If the syrup
has evaporated slightly, add enough water to equal 1/3 cup syrup.
VARIATIONS:
