Our new neighbors have just arrived from Grenoble and they are coming for dinner on Sunday. They're bringing the cheese for dessert. I think I'll start with the white gazpacho and I'd like to include the summer squash gratin--which is as close to a perfect dish as I can imagine. So: I'm looking for ideas for the main. I will have time to cook and there aren't really ingredients off the table, but it is late summer in northern California, so the produce--especially the tomatoes-- are amazing. Ideas?