Judy's cocoa cake

This is a family recipe...I think? Though I don't know why it's "Judy's"...
My mom made it for my birthday for the first ten or so years of my life, so it's somewhat of a tradition in any case. It's got a nice, deep chocolate flavor.

Makes 2 9" round layers.

Ingredients
2 c sugar
3/4 c butter
1/2 c cocoa
2 c flour
1 t vanilla
1 c cold coffee (instant mixed with water works as well)
1 t baking powder
2 eggs, well beaten
1 t baking soda dissolved in 1/2 c warm water

Directions
1. Preheat the oven to 350F.
2. Mix cocoa & sugar and cream them with the butter.
3. Sift together the baking powder and flour.
4. Add flour mixture and coffee alternately to the butter mixture.
5. Add eggs, vanilla, water & baking soda last.
6. Pour into two greased 9" round pans.
7. Bake for 30 min, or until a toothpick comes out clean.