3 tablespoons cold extra-strong coffee or espresso
1 tablespoon fresh lemon juice
1 teaspoon cream of tartar
1 teaspoon vanilla
1/4 teaspoon almond extract (optional)
Increase the mixer speed to medium (not high) and beat until the mixture increases in volume 4 1/2 to 5 times and resembles a bowl of slightly translucent soft foam composed of tiny bubbles. (This takes anywhere from 1 1/2 to 3 minutes.) The foam will hold a very soft, moist shape when the beaters are lifted. Beat in gradually (on medium speed), 1 tablespoon at a time, taking 2 to 3 minutes:
3/4 cup sugar
When all the sugar has been added, the foam will be creamy white and hold soft, moist, glossy peaks that bend over at the points; do not beat until stiff. If the mixer bowl is nearly full, transfer the mixture to a wide 4- to 6-quart bowl for easier folding. Sift a fine layer of the flour mixture (about one-eighth of the total) evenly over the surface of the batter and fold gently with a rubber spatula only until the flour is almost incorporated. Do not stir or mix. Repeat 7 more times, folding in the last addition until no traces of flour are visible. Pour the batter into the pan and tilt or spread to level the top. Bake until a toothpick inserted in the center comes out clean, 35 to 40 minutes. Let cool upside down for at least 1 1/2 hours, setting the tube over a bottleneck or resting the pan on 4 glasses. Unmold. Serve plain or frost with:
