That's the old standard Depression cake. It is also called One Pan and Eggless, Milkless. It's very good, but I didn't read the whole recipe so I'll add, in case it doesn't say, that a cup of coffee for the water makes a big difference in the intensity of the chocolate. It's a moist cake so I would line the DO when baking it.
Here's the one I make quite often.
1 1/2 cups (6 1/4 ounces) King Arthur Unbleached All-Purpose Flour
1 cup (7 ounces) sugar
1/4 cup (3/4 ounce) cocoa
1/2 teaspoon salt
1 teaspoon baking soda
1 teaspoon vanilla
1 tablespoon (1/2 ounce) vinegar
1/3 cup (2 5/8 ounces) vegetable oil
1 cup (8 ounces ) cold coffee
I sprinkle powdered sugar over the top while it's still warm.
I suppose a person would have to double it in a 12" DO.