Thank You Cake

I made this cake as a thank you to my older cousins, as they had let me borrow their car for 2 weeks while I was home at Easter. This is just a simple chocolate sponge with chocolate buttercream, and only took about an hour to make, including time in the oven, although as I was in a bit of a rush I didn't let it cool fully.

Something like this is so simple to make, but I think it is a nice gesture and a good way to say thank you.