I can't believe I have never done this technique before! It is called Faux Patina and the tutorial by Angie Leach can be found here on Splitcoaststampers. It is very, very easy and you probably have the supplies on hand!
Basically it involves lots of sponging and a little gold embossing. I used Crumb Cake as my base, then added some Not Quite Navy, Always Artichoke and Early Espresso. The last step is to lightly ink with Versamark™ and emboss with gold embossing powder. You must have a light touch or the gold will cover up the sponged on color. I am hoping to experiment with some different color combinations, maybe something with Cherry Cobbler!