-
1
Cut onions into slices about 1/4 inch thick.
-
2
Chop coarsely.
-
3
Heat butter and oil in heavy skillet.
-
4
Add onions and cook, covered, over medium heat about 10 minutes, or until onions are limp and begin to render liquid.
-
5
Add pinch of sugar.
-
6
Uncover onions and cook over medium-high heat 30 to 45 minutes.
-
7
Stir frequently with a wooden spoon or spatula to scrape up brownings in pan.
-
8
The onions should be a deep brown and reduced to a small mass.
-
9
They must be watched carefully and stirred to prevent scorching and to ensure even browning.
-
10
Transfer onions to a bowl.
-
11
Add wine to skillet and boil, scraping up pan brownings, until liquid is reduced to a thick glaze.
-
12
Add glaze to onions, along with salt, nutmeg, cream and egg.
-
13
Adjust seasoning.
-
14
(Dish may be prepared to this point a day in advance and refrigerated.)
-
15
Preheat oven to 375 degrees.
-
16
Grate cheese and distribute half of it on bottom of chilled pastry shell in pastry tin.
-
17
Distribute onion mixture evenly over cheese; top with remaining cheese.
-
18
Bake 40 to 45 minutes.
-
19
If top browns too much, reduce heat slightly toward the end.
-
20
Serve as a first course, warm or at room temperature.
-
21
Tart can be made a few hours ahead, but do not refrigerate.
