Some ideas for things to add between the potato layers (this is where the infinite adaptation comes in):
- Cremini or shiitake mushrooms, thinly sliced and sauteed with a thinly-sliced shallot
- A few handfuls of spinach, sorrel, or chard, chopped small, sauteed with a little minced garlic or shallot
- Summer squash, thinly sliced and sauteed (make sure you salt and drain the slices first to remove excess water)
- Leeks, sliced into 1/2-inch half-moons, and softened in a skillet with a little butter
- Chopped fresh herbs such as parsley, chives, thyme, or a little rosemary
- Bacon, chopped small and crisped, or crumbled sausage, browned
INFINITELY ADAPTABLE POTATO GRATIN
adapted from smittenkitchen.com
serves 4-6 generously, also reheats beautifully!
3 tablespoons butter, cut into pieces, plus an additional pat for buttering gratin dish
about 1 1/2 pounds potatoes, unpeeled if skins are thin and tender
salt and freshly ground black pepper
1 cup milk, half-and-half or cream (if using something richer than milk, you can skip the butter)
2 ounces cheese, grated or crumbled (Parmesan or Gruyere are the classics, but goat cheese, blue cheese or any of your favorites will work too -- we used the ends of a couple of hard cheeses from Cherry Grove Farm)
Preheat the oven to 350°F and grease a 9- by 12-inch baking dish with the pat of butter. Slice the potatoes very thinly and arrange them in a layer, overlapping the edges slightly like shingles. Sprinkle the potatoes with plenty of salt and freshly ground pepper and a third of the cheese (and, if you are using a sauteed vegetable filling, this is where you’d want to add half of it) before repeating this process with your remaining potato slices. Depending on how thinly sliced your potatoes are, you should end up with approximately three layers, with a third of the cheese between each layer. Reserve the last third of your cheese for later.