Special Extra
Prepare as directed, adding one or more of these fabulous stir-ins to potato mixture before spooning into casserole dish: roasted garlic, caramelized onions, chopped fresh chives, grated horseradish or crumbled cooked bacon.
Substitute
For extra colour, substitute unpeeled red potatoes for the peeled baking potatoes.
Make Ahead
Assemble casserole as directed, but do not bake. Refrigerate up to 2 days. When ready to bake, uncover and bake as directed, increasing baking time as needed until potato mixture is heated through and topping is lightly browned.