For what it’s worth, gratin refers to the cooking vessel and the way it is used, not just the dish itself. Anything can be cooked “au gratin” and the recipe itself is varied. Potatoes alone, or mixed with other roots such as parsnip, turnip, or onion. Mushrooms, kale, artichoke hearts, olives, all these can go in as well. The dish can be made with or without cheese, with cream, milk, stock, or any combination of these. In summer, I make gratins with vegetables that are “wet” (tomatoes, eggplant, etc.) and the only liquid I use is a little bit of flavorful olive oil. In colder months I make traditional creamy, cheesy gratins with roots and tubers. You can be precise in the way you lay in the ingredients or you can be casual. Bear in mind that the thickness of the cuts, the density of the vegetables, and how tightly packed in the dish everything is can affect the cooking times. This recipe is a variation of a quiche I used to make, and it is named for Denise who likes it so much I can never make enough.