Tarte a l'oignon

So a couple of weeks ago I see David Lebovitz's recipe for tart crust and I tell myself, "I've got to try this!" As fate would have it, I was scheduled to make Tarte à l'oignon, and so the magic began. A few weeks ago I posted a recipe from my French desserts cookbook; this recipe is from a beat-up old paperback omnibus called Cuisine Sans Souci by Rose Montigny, copyright 1981 and a publication of Cuisine et Vins de France. It's a no-nonsense little book--no pictures, terse instructions--but the recipes tend to be quite good. And it's a fabulous introduction to French food culture--like Joy of Cooking it has a little of everything, including menus, what to cook if you don't have much time, what to cook on a budget, and what to cook for children. As a mom, I find that chapter somewhat hilarious reading. Have an infant of less than a year? How about some Carottes Râpées au Petit-Suisse (grated carrots with creamy cheese) or some Crème à la Fleur d'Oranger (orange flower custard)? If that were my kid, it would be one bite for baby, two bites for Mommy...
But back to the tarte. This was a simple recipe, meant to be a first course. I added a few things and made it a main course. It would be delicious with salad, but I hate making salad, so I put the salad greens in the tarte, and that turned out just fine.

Tarte à l'oignon
Adapted from Cuisine Sans Souci

Tart pastry (see below)
about 1 lb. sliced onions
4 T. butter
about 1-1/2 cups cream or sour cream (the recipe called for crème fraîche, which I can't get here--I used light sour cream)
4 eggs
a handful of grated Cheddar or Gruyère or Parmesan, or a combo--whatever you've got
a handful of crumbled feta
a couple of big handfuls of salad greens or baby spinach
Salt, pepper, fresh grated nutmeg

Preheat the oven to 400. If you're making David's tart pastry, you can put together the butter and all and put it in the oven while it's preheating. I made his pastry with more salt (about 1/2 t.), less sugar (also about 1/2 t.), olive oil, and about 50 grams of whole wheat pastry flour and 100 grams white flour. Loved it! If you want to go more traditional, I belive that Elise at Simply Recipes has a good pâte brisée recipe. You'll want to chill that, though. With David's recipe, you can just forge on. I didn't even pre-bake it--this no-nonsense French cookbook doesn't stand for that :-).
So, while your tart dough is heating and/or cooling, sauté those onions (and maybe a pinch of salt) in the butter. They don't have to caramelize or anything, but cook them down until they're quite soft. Add the greens to wilt and let the mixture cool for a bit while you get the rest ready. Whisk together the eggs, cream, and feta, and add salt, pepper, and nutmeg to taste. Sprinkle the "hard cheese" on the tart crust. Put the onions/greens on top of that, and pour the egg mixture over that. If you're using a tart pan with a removable bottom, put it on a cookie or baking sheet, for goodness sake! Then put it in the oven and bake for about 35 minutes. You can serve it hot or warm, and the cookbook suggests drinking a nice Alsatian white with it. Yum!