Zwiebelkuchen (German Onion Pie)

I actually made this "Onion Pie" a couple weeks ago, but wanted to post it this week while I'm actually in Germany! My co-worker, a native of the Black Forest region of Germany (in the southwest), told me about this dish in September after his sister reminded him that it was "Zwiebelkuchen season." Apparently every year, around late September, these onion pies pop up in every German bakery and kitchen. They are traditionally served with early-harvest wine, which is a barely fermented wine -- and often even just served with grape juice. I didn't eat my slice with a light wine, but I can see how it would be a good pairing since the pie has such a rich taste. The pie filling is made by sauteing over 3 pounds of onions with bacon for almost an hour, really caramelizing the onions and condensing them to nice sweet (and bacon-salty) flavor. This mixture cools down a little before adding sour cream and egg, and then is poured into it's pie shell (in this case, a yeast-dough galette). The filling here is very similar to the traditional dish (although sometimes made with cream instead of sour cream). The crust is traditionally more of a flaky pie crust, rather than the yeast dough used here.

My German friend gave it two thumbs up! So I did something right...


RECIPE:
Zwiebelkuchen-inspired Galette
from Gourmet (November, 2009 -- sadly, the last issue!)
serves more than you would think, since it's so hearty and rich!

INGREDIENTS:
DOUGH:
1.5 teaspoons active dry yeast
1/3 cup warm milk (105-115F)
1/4 teaspoon sugar
2 cups all-purpose flour
1/2 teaspoon salt
1 egg
1/2 stick (2 ounces) butter, melted and cooled
egg wash (one egg and one teaspoon water, whisked), optional

FILLING:
3.5 lbs onions, thinly sliced
1/4 lb. bacon, finely chopped
1/2 stick (2 ounces) butter
1 cup sour cream (I used low-fat, but with all that bacon does it really matter?)
2 egg yolks

DIRECTIONS:
Dough:
Stir together yeast, milk, and sugar in the bowl of a stand mixer fitted with paddle attachment (or in a bowl to mix by hand) and let stand until foamy, about 5 minutes. If mixture does not foam, start over with new yeast.

Add flour, salt, egg, and butter and mix at low speed (or stir) until a dough forms. Increase speed to medium-high and beat 3 minutes (or kneed by hand about 5 minutes).

Sprinkle dough lightly with flour and cover bowl with a kitchen towel or loosely with plastic wrap. Let dough rise in a draft-free place at warm room temperature until doubled, 1.5-2 hours.

Filling:
Cook onions and bacon in butter with 1 teaspoon of salt and 1/2 teaspoon pepper in a 12-inch heavy skillet, covered, over medium-high heat, stirring occasionally, until onions are softened, about 20 minutes. Remove lid and cook, stirring occasionally, until onions are golden, 20-30 minutes. Cool onions. Whisk together sour cream and egg yolks, then stir into onions.
The onion-bacon mixture can be made up to 3 days ahead, and chilled. Bring to room temperature before adding sour cream and egg yolks.

Bake:
Preheat oven to 375F with rack in the middle.
Roll out dough on a lightly floured surface with a lightly floured rolling pin into a 12-inch circle. Fit dough into a springform pan (stretching slightly if necessary to hang over edge) and spread filling evenly in it. Fold edges of dough over filling, leaving some filling exposed in the center. I brushed my pie with a little egg wash to give it a little shine, but this is optional. Let pie stand 20 minutes at room temperature.
Bake until crust is golden-brown and filling is bubbling, about 1 hour and 15 minutes. Cool slightly before serving.
Alternatively, pie can be made one day ahead, chilled, and reheated uncovered in a 350F oven for 30 minutes.