Fimo clay, or some of the bead clays will work.
I had a friend do an entire Thanksgiving dinner, including a salad and dressing, using Fimo, or
Super Sculpy clay. It is a low temperature baking clay that will harden at about 250° in the oven.
Roll some white, press some beige or brown, wrap the brown around the white, shape like bread, slice and then bake.