So there was that scheme to cook up a mess of scalloped potatoes in the crockpot, so as to simplify my contribution to the Christmas Eve potluck down at the Cult Headquarters. Alerted by Frugal Scholar to the likelihood that milk and cheese would curdle during the long cook, I sent out intelligence feelers across the Web. One, count her, (1), authoritative writer offered a true scalloped potato recipe, complete with white sauce and cheese, and claimed it worked well. Everyone else said if you put dairy in a crockpot you’ll end up with curds and whey.
Well, I liked Stephanie O’Dea’s basic idea, which she billed as au gratin rather than scalloped and to which she added walnuts and sage. I happen to have a sage plant that’s struggling to survive the winter frosts and a bucket of Costco walnuts in the freezer. But given the wackiness of the Christmas schedule, I really didn’t want to take a chance on ruining several pounds of potatoes and being left at the last minute with nothing to take to the chivaree.
So… I decided to substitute a velouté sauce—in effect, a white sauce made with chicken stock instead of milk—and then add the gruyère topping at the last minute. This worked pretty well. Here’s how it fell out:
To make enough to choke a horse:
• several pounds of potatoes, peeled
• about four handfuls of walnuts
• four to six fresh sage leaves, minced or finely chopped
• one large yellow onion
• butter in abundance
• olive oil
• 2 Tbsp flour
• 2 cups flavorful chicken stock
• salt and pepper
• a cup or more of grated gruyère (or other) cheese
I happened to have a box of College Inn’s “White Wine and Herbs Culinary Broth,” according to the ingredients panel your basic chicken stock with wine added. It tastes more like they used sherry—their “wine” must be cheap and sweet—but it’s pretty good. But you could use just about any broth, fresh or canned, wine-spiked or not.
Slice the potatoes and onions fairly thin—I used a mandoline for both, creating potato slices about 1/8 inch thick, but if you used a knife, about 1/4 inch would be fine.
Skim a frying pan with olive oil and sauté the onions until they’re just starting to carmelize. In a small frying pan or wide stockpot, melt some butter and toast the walnuts. When the onions are beginning to brown, add the sage and stir to mix well.

Make the sauce velouté: melt a couple tablespoons of butter in a saucepan. Add a like amount of flour. Stir over medium heat until the butter foams, but do not allow to brown. Add the chicken stock and heat over medium high heat, stirring occasionally, until the sauce thickens.
Generously butter the crockpot’s ceramic pot. Starting with potatoes, layer in the ingredients this order: potatoes on the bottom, dabs of butter, another layer of potatoes, layer of onion/sage, half the toasted walnuts, half the sauce; layer of potatoes, dabs of butter, layer of potatoes, remaining walnuts, layer of onion/sage, remaining potatoes, remaining sauce.
Cook on “low” about 5 or 6 hours.
A half-hour before serving, remove the cover, sprinkle the gruyère over the top, and replace the cover. Allow to cook until the cheese melts.
Ours cooked about six hours. I think that may have been a bit too long for Idahos, because the result, while extremely tasty, was somewhat mushy. Next time, I’d use boiling potatoes (red or white), which should hold their shape a bit better. Stephanie’s recipe calls for cooking the dish on “high” for just three hours; this also might solve the overcooking issue.
I’m fairly certain that you could get away with pouring a cup or so of heavy cream over the top at the time you put in the cheese—about a half-hour before serving. Even though the potatoes are very hot by then, I very much doubt the cream would fall apart in a half-hour. But since I had to sing at the 8:30 service as well as the midnight eucharist, SDXB would be bringing the potful of potatoes to the intermission potluck; setting him to experimenting with cream minutes before he had to haul the stuff to the car…well, that would’ve been asking for trouble.
Although it wasn’t a pretty dish, it really tasted very good, and the diners left little to bring home.