Hello! 

I've been asked to do 'dark green' cupcakes for an upcoming party. The colored batter is to represent a country's colors.

My first thought was green velvet cake because the color is really intense in it, but for some reason I'm no good with velvet cakes in general. 

Velvet cakes rise because of the reaction between baking soda and vinegar, right? Mine never rise. 

So, I thought I'd make a normal yellow cake (Using baking powder for leavening), and sub out about two tablespoons of the flour for cocoa powder, and add two tablespoons of green liquid food coloring to the wet ingredients- what are your thoughts on this? Can it work, or should I just stick with a velvet cake recipe?

Thank you so much for your time and consideration ^_^ I'm an amateur baker and would really appreciate your help.

I think you should just make the yellow cake recipe and add green food coloring, without doing substitutions.   Mix in a hint of black food coloring to get the dark green!

Thank you. Black food coloring is really hard to get where I live, though, which is why I thought cocoa powder would do instead! I suppose a small amount will do no harm. Again, thanks for your time!