recipe for chocolate frosting?

[onesnap]

I don't have a double boiler or anything fancy. I was looking for an easy chocolate frosting recipe (with real butter etc is good). I think I will frost once I get to where I'm going...it will have to live in a tupperware in the fridge until I have a chance to frost.

I would love something similar to the Trader Joe's frosting that they used to sell. I would use it on yellow cupcakes. I usually use chocolate covered sunflower seeds in bright colors to make flowers on each cupcake.

Thanks for your help!