I know it’s been said about all sorts of things, but this is the stuff that dreams are made of. I mean it.

Our recent discussion of eating, sleeping, and breathing food got me thinking, a dangerous activity that inevitably ends with me hunched over a pile of open cookbooks and recipe clippings. In that post, I’d mentioned a roasted-onion tart that once came to me in a dream, beckoning from a shelf in a bakery window, its thick topknot of translucent onion gleaming under the lights. Unfortunately, I’ve never seen its exact likeness in my waking life, but dear reader, I’ve come close. If the onion tart in my dream was, let’s say, the Platonic form of onion tarthood, its real-life copy is the Alsatian onion tart. And deep within my accordion file of clippings lies the recipe.

A specialty of the Alsace* region of northeastern France, la tarte à l’oignon is perfect winter fare: delicate but rich, sweet but earthy, light but grounding. I made it for the first time—and then over and over and over again—last winter. It begins with a hefty amount of thinly slivered onions, sautéed until lightly caramelized and then doused with a mixture of egg and heavy cream, poured into a tart shell, and baked to golden.

Every onion comes into the world hoping to find its end in this tart. As the French would say, “C’est mortel!” (It’s killer!). Me, I say it’s just plain dreamy. I’d like to stretch out on its bed of onions and custard and rest my head on a firm pillow of pâte brisée. Never mind the little details, like the shards of buttery pastry in my hair. One could find worse places to hibernate for winter.

*Alsace is also, incidentally, the home of choucroute garnie, a traditional dish of sauerkraut and various forms of pork. Those Alsatians are brilliant.

Tarte à l’Oignon, or Alsatian Onion Tart
Adapted from André Soltner in The New York Times, October 20, 2003

No matter what recipe she was talking about, my father’s mother—a little Jewish woman from Poland with dyed red hair and a thick accent—would always begin by saying, “First, you brown an onion.” Too bad she never got to taste this tart. It makes a nice lunch or a light supper when served with a simple green salad, some good bread, and a crisp, dry Alsatian white wine, such as Pinot Blanc.

1 half-recipe Martha Stewart’s pâte brisée without sugar (flaky pie dough; enough for one 9” tart shell), unbaked
1-2 Tbs olive oil
1-1 ½ lbs yellow onions (about 2 large), peeled and very thinly sliced
1 large egg
½ cup heavy cream
Freshly ground pepper
Grated nutmeg

Preheat the oven to 375 degrees.

Roll out the pâte brisée, and line a 9” removable-bottom tart shell with it. Cover it with plastic wrap, and chill it in the refrigerator.

Heat the oil in a large skillet over medium heat, and sauté the onions, stirring regularly, until they are lightly golden—just beginning to caramelize—and tender. Remove the skillet from the heat.

In a small bowl, beat the egg and cream together. Add a pinch or two of salt and pepper and a pinch of nutmeg. Add this to the onions, stirring to combine.

Remove the tart shell from the refrigerator, and fill it with the onion and egg mixture. Bake tart for 25 minutes, or until the filling is golden brown and set. Serve hot or warm.

Serves 5 to 6.