I have no idea where that original recipe came from. It might have been something I brought home from Girl Scouts. And I'm pretty sure that recipe didn't state a source - it was just a recipe typed on a page.
The name is just as mysterious. I'm guessing it was "wacky" because all the ingredients were mixed in the same pan you baked in. OOooohhh ... so radical.
To be honest, I find it easier to do the mixing in a bowl. Trying to get ingredients mixed in a baking pan and getting all the way into the corners isn't all that fun. Sure, if you use a bowl, it's one more thing to wash. But it's not a big deal.
Wacky Cake V2.0
1/4 cup cocoa
1 1/4 cups sugar
1 teaspoon baking soda
1/2 teaspoon salt
1 cup water
1 tablespoon balsamic vinegar*
1/4 cup cooking oil
1 teaspoon butter vanilla emulsion (or vanilla extract)
1/2 cup semisweet chocolate chips (or as desired)
Preheat your oven to 375 degrees and spray an 8- or 9-inch square cake pan with baking spray.
Combine cake flour, sugar, cocoa, baking soda in a bowl and whisk to combine. If your cocoa is a little lumpy, you can run it through a sifter, if you like.
Mix the vinegar and water together in a cup or small bowl.
Add the vinegar-water mixture, oil, butter-vanilla emulsion, and egg to the dry ingredients. Stir to combine well.
Pour the mixture into the prepared pan, smooth the top of the batter. Bake at 375 degrees until the top springs back when lightly touched, and a toothpick inserted in the center comes out clean. Start checking it at about 35 minutes - the actual baking time will vary a little depending on the pan you use.
Remove the cake from the oven and sprinkle the chocolate chips on top of the cake. Wait about a minute, then spread the now-melted chocolate over the cake to frost it.
Let the cake cool completely before serving. I served it straight from the pan. It's that kind of cake.
*I used a vanilla fig vinegar for this, but a plain balsamic vinegar would be fine. You don't need a high-quality balsamic, but if you have a flavored vinegar that you think would pair well with chocolate cake, you can use that. A raspberry or pear balsamic would be fine. Anything with herbs would be a little iffy.