Mix the cake ingredients together well (dry ingredients first, then add wet ingredients), I use my Bosch mixer. Bake for 25-30 minutes or until the top feels set. Don't overbake.
Mix the frosting ingredients together well, and spread onto the cake once it's cool. It's not going to look like enough, but it works out to be perfect, even after the kids (and maybe mom) do some sampling and taste-testing.
Melt the chocolate chips and butter in a saucepan on low heat until smooth. Let cool and use a spoon to drizzle it around, OR spoon into a baggie (or pastry bag) with a small corner cut off. Pipe it through onto the cake in whatever pattern you feel like.
Double the cake recipe for 3-9" pans, but you may need even more frosting than double if you're making a layer cake with frosting between the layers plus more for decorating.