Place a colander in a 2-quart glass measure or medium bowl. Line colander with 4 layers of cheesecloth, allowing cheesecloth to extend over outside edges. Spoon yogurt into colander. Cover loosely with plastic wrap; refrigerate 12 hours. Spoon yogurt cheese into a bowl; discard liquid. Cover and refrigerate.
Combine 1/2 cup sugar, water, and espresso granules in a small saucepan, and bring to a boil. Cook 1 minute over medium heat, stirring occasionally. Remove from heat, and stir in Kahlúa. Cool completely.
Combine yogurt cheese, 1/2 cup sugar, milk, vanilla, and mascarpone cheese; beat at medium speed of a mixer until smooth. Set aside.
Combine cocoa and chocolate in a bowl.
Cut angel food cake into 12 slices using a serrated knife. Dip cake slices into espresso mixture; place 4 slices crosswise in a 9 x 5-inch loaf pan. Gently spread one-third of cheese mixture over cake layer, and sprinkle with one-third of cocoa mixture. Repeat procedure with the remaining cake slices, cheese mixture, and cocoa mixture. Chill torte at least 2 hours.