There is no one definitive recipe for Hershey's dark chocolate cake. However, a quick search online will reveal a number of recipes that claim to be the original or definitive recipe.
COMBINE ALL DRY INGREDIENTS IN A LARGE BOWL.
ADD ALL OTHER INGREDIENTSEXCEPT FOR THE BOILING WATER.
BEAT UNTIL WELL MIXED, ABOUT 2 MINUTES ATMEDIUM SPEED.
STIR IN BOILING WATER (BATTER WILL BE THIN).
POUR INTOGREASED PAN (EITHER 1, 9 X 13 OR 2, 9 ROUND).
BAKE AT 350 DEG F FOR 30TO 35 MINUTES FOR ROUND PANS OR 35 TO 40 FOR SHEET PAN.
COOL 10 MINUTES INPAN, THEN REMOVE TO WIRE RACK AND COOL COMPLETELY.