Depression Cake

After the success of my skinny lemon cakes, I've been looking for other eggless cake recipes that do not require butter either. The Depression Cake (so named because it was invented during the Depression when ingredients were in short supply) seemed to fit the bill, and I lost no time in trying it out.
Unfortunately, the cake seemed to have taken its name too seriously, and every single cupcake sported a depression in the middle. I filled it up with chocolate sauce to make it presentable, but one would still like to know whether to attempt the recipe again or not.

What I did do wrong was to go by my nose and turn off the over when 7 minutes of baking time were left (toothpick test was successful). A few minutes later, I realised I might have made a mistake and popped it back in for 7 minutes, but by then the damage was probably done. That might be the reason for the crater.

1 1/2 cups flour (all-purpose)
3 tbsp cocoa
1 cup sugar
1 tsp baking soda
1/2 tsp  salt

1 tsp white vinegar
1 tsp vanilla extract
5 tbsp vegetable oil
1 cup water

Method:
Preheat oven to 175 degrees.
Mix first 5 dry ingredients.
Make 3 depressions in dry ingredients - two small, one larger. Pour vinegar in one depression, vanilla in the other and the vegetable oil in third larger depression.  Pour water over all.  Mix well until smooth.
Line a muffin tin with cupcake liners, put the batter in them (this amount made 12 cupcakes), and bake for 25 minutes