No need to visit a coffee house when this mocha-inspired cake is on-hand. Perfect for any coffee break!
Preheat oven to 325° (160°C ). Place oven rack to the lowest position.
In small glass measuring cup, combine coffee and boiling water; let cool.
In large bowl, whisk flour, sugar, baking powder and salt. Add water, oil, egg yolks and cooled coffee mixture; beat with electric mixer until smooth. Set aside.
In separate large bowl, with clean beaters, beat egg whites and cream of tartar on high speed until stiff peaks form, about 2 minutes. Fold one-quarter of the egg whites into egg yolk mixture. Gradually fold in remaining egg whites until no streaks remain. Scrape into ungreased 10-inch (25 cm) tube pan.
Bake for 75 minutes or until top springs back when lightly touched. Turn pan upside down and let hang on legs attached to pan or on a bottle, until completely cooled, about 2 hours. Run knife around inside of pan and tube. Turn out, bottom side up, onto cake plate.
In glass measuring cup, combine coffee and hot water to dissolve. Whisk in icing sugar and vanilla. Add water one tablespoon (15 mL) at a time until smooth and consistency of thick syrup. Spoon over the top of cooled cake, allowing to drip down the sides. Let set before serving.
- When beating egg whites for any foam cakes, be sure to use clean and dry beaters and bowl. Do not use a plastic bowl. Even a speck of grease or egg yolk will prevent egg whites from beating properly.