Sift flour, 1 cup of the sugar, baking powder, and salt into a medium-size bowl. Make a well and add in order: Oil, egg yolks, water, and coffee; beat with a spoon until smooth. Beat egg whites and cream of tartar in large bowl of mixer until foamy-white and double in volume.

Beat in remaining 1/3 cup sugar, 1 tablespoon at a time, until meringue stands in firm peaks. Gradually pour egg yolk mixture over beaten whites, gently folding in until no streaks of white remain. Spoon into ungreased 10-inch tube pan.

Bake in slow oven (325°F) 1 hour and 10 minutes, or until top springs back when lightly pressed in center with fingertip. Invert pan, placing tube over a quart-size soft-drink bottle; let cake cool completely. When cool, loosen cake around outside edge and tube and down sides with a spatula.

Cover pan with serving plate; turn upside down; shake gently; lift off pan. Drizzle mocha glaze over top of cake, letting it run down the side.

Mocha glaze:

Melt butter with chocolate in a small heavy saucepan over very low heat; stir until blended. Remove from heat; stir in coffee and cinnamon. Add sugar alternately with hot water, beating until smooth.

Makes enough glaze for top of one 10-inch tube cake