Collector's Cocoa Cake

This is a cake I made for a Halloween dessert I will feature tomorrow. I just needed a simple, one layer chocolate cake. I would have gone with my usual chocolate cake recipe, but it doesn't halve well, and I really only wanted one layer.I found this recipe in my giant Hershey's recipe binder. It actually made two round cakes, but I was brave and halved the recipe, which worked well. I discovered after it was baked that I halved every ingredient, but I forgot to use one egg instead of two. This didn't seem to matter though. It actually made a really high-rising cake that took a little longer to bake, but it was good! 
Here is the original recipe.

Collector's Cocoa Cake
3/4 cup butter or hard margarine, softened
1 3/4 cups granulated (white) sugar
2 large eggs
1 teaspoon vanilla extract
2 cups all-purpose flour
3/4 cup unsweetened cocoa powder
1 1/4 teaspoons baking soda
1/2 teaspoon salt
1 1/3 cups water

Preheat oven to 350◦F. Grease and flour two 8 or 9 inch round baking pans.
In a large bowl, beat the butter and sugar until fluffy. Add the eggs and vanilla, beat for one minute. Stir together the flour, cocoa, baking soda, and salt, add alternately with water to butter mixture, beating until well blended. Pour batter into prepared pans.
Bake for 30-40 minutes (depending on pan size) or until a toothpick inserted in the center comes out clean.

West Side Publishing. "Collector's Cocoa Cake." Recipe. Hershey's Classic Recipes, Lincolnwood Illinois: Publications International, Limited, 2009. 72.