POTATO CASSEROLES

THIS CHAPTER INCLUDES CASSEROLES IN which potatoes are the star. We begin with a recipe for shepherd's pie-basically lamb stew topped with mashed potatoes. Traditional recipes for shepherd's pie start with leftover roast leg of lamb. We wanted to develop a recipe that did not start with leftovers that many cooks are unlikely to have. We tested ground lamb, and although this made a credible filling, it was not as richly flavored and toothsome as we wanted. We then tested meaty (and relatively inexpensive) shoulder chops, which are our favorite for lamb stew. They worked beautifully, giving the falling a hearty lamb flavor and chewy (but not tough texture) that contrasts nicely with the smooth mashed potato topping.

We tried using regular mashed potatoes as the topping for this casserole, but they started to break down in the oven. Adding two egg yolks gives the mashed potatoes more body and helps them hold their shape.

Scalloped potatoes, thinly sliced rounds of potatoes baked with dairy and usually cheese, are a classic side dish. To bring this dish up to the level of a main course, we devised two different strategies. Our first was to layer many more potatoes than is customary into the casserole dish. This worked just fine. Our second concerned the "sauce" for the potatoes, which is traditionally made from heavy cream. We found that this worked fine, although we felt the rich cream needed some contrasting flavors. Simmering a little garlic, cayenne, nutmeg, salt, and pepper in the cream added the extra level of flavor we thought was needed.

To make sure that all of the potatoes in this recipe (almost five pounds) fit into the baking dish, it is necessary to layer the slices with some care. We also found it helpful to compress the layers with a spatula several times during baking. This gives the casserole a substantial texture, while also allowing the cream to circulate completely around the potatoes, helping to brown the top layer.

The New England Scalloped Fish and Potato Casserole is less fussy than the all-potato scallop because there is no layering of the potatoes in the pan. The potatoes need to be precooked on the stove top so that the fish does not overcook. At this point, the potatoes slices are simply poured into the baking dish, the fish is added, and the casserole is briefly baked. This dish is also looser than the potato scallop because the sauce does not cook down so much in the oven.

As for flavoring these scalloped potato casseroles, we prefer bacon. Ham could be used, but we like the strong, salty flavor of bacon best. We found that the fish casserole also benefited from the addition of smoked trout, which added another level of seafood flavor to this dish.