I have a question about the recipe "Individual Sweet Potato Gratins with Creme Fraiche, Onions, and Bacon" from Erin McDowell. This is delicious and I want to make it a large batch for Thanksgiving. It took forever to cook with one large sweet potato and other people said they had trouble with long cook times when they made larger batches. Does anyone have any recommendations about how long to expect this to cook based on number of sweet potatoes used? Also, do I want to pile the sweet potato pieces deeper or use a wide, shallow dish to keep to 4-6 layers when I cook it?