Delta Mocha Chiffon Cake

This must-bake cake is filled with delicious flavor. From one smooth slice, you will taste the moist layers of cake, fondant icing and a special chocolate-coffee filling made from buttercream. Your guests will surely be delighted.
Combine the first 3 ingredients until smooth; allow to cool.Combine the flour and the following 3 ingredients in a large mixing bowl. Add the cocoa mixture, egg yolks, butter and vanilla; beat on medium speed with an electric mixer until smooth.Beat the egg whites and tartar on high speed with an electric mixer until frothy. Roll in the dough. Pour the batter into 4 oiled and floured 9-inch round baking pans.Bake 2 layers at a time at 325 ° C for 17-20 minutes or until a wooden stick inserted in the middle comes out clean. Cool the cakes in the tins on a wire rack for 10 minutes. Remove from the pan and refrigerate on wire racks covered with plastic wrap or waxed paper to prevent layers from sticking to the wire racks.Spread about 1/2 cup of the chocolate-coffee cream filling between the layers. Cover with chocolate fudge frosting. Decorate if desired. Store in the refrigerator.