Makes 2 long pans, enough for 70-100 servings, depending on how you cut it and how hungry folks are! You could probably stretch the batter into 3 long pans if necessary, for less-tall cakes that bake more quickly.
If you want to make a single 9x13" sheet cake, just use 1/4 of the ingredients and bake for slightly less time.
10.5 cups (1575 g.) All-purpose flour
6 cups (1350 g.) Granulated sugar
3 cups (340 g) Dutch process cocoa
6 Tbs. Baking soda
3 Tbs. Salt
~8 cups water
2 1/4 cups Canola/vegetable oil
1 cup + 2 Tbs. White vinegar
6 Tbs. Vanilla extract
30 oz. (two bags) Dark chocolate chips
Preheat oven to 350 (convection/"speed bake")
Sift/mix dry ingredients in large bowl.
Combine wet ingredients; fold into dry, adding water if necessary to get consistency of thick pancake batter.
Pour into oiled pans and bake for ~45 mins., or till knife comes out clean.
Immediately sprinkle chocolate chips evenly over top of cake; cover for five minutes, or until you can spread chips evenly with rubber spatula (be gentle with this step). Let cool completely before slicing, if possible.