Onion tart

Winter weather has arrived too early, a days-long deep freeze that ended the gardening season quicker than the Yankees dispatched the Twins, alas.  So, for a school potluck this evening, I thought an onion tart would be good.  My daughter thought otherwise - she wanted me to bake a dessert, and when I told her what I was making she complained, "Aww, only the adults are going to like it!"
I love how much onions change when they're slow cooked, and a good tart showcases them perfectly.  Tarts are good for an appetizer, a first course, or an easy dinner, and depending on what kind of pan or tray they're cooked in, they can be elegant or rustic.  I use a bit of whole wheat flour in the crust so it has a nice color and texture.  Cooking the onions takes a bit of time, but the recipe is pretty simple.

Crust
1 cup unbleached flour
1/4 cup whole wheat flour
2 tablespoons duck fat
3 tablespoons butter
1/2 teaspoon salt
1 egg, beaten
ice water

Mix flours in bowl, add salt and fats, mix with fingertips until pebble-sized.  Add egg and mix.  Add enough ice-cold water to hold dough together, mixing long enough before further additions of water to ensure that liquid is absorbed and distributed through flour.  Form into ball, flatten slightly, wrap in plastic (I put it into a sandwich baggie) and refrigerate.

Tart
3-4 tablespoons butter
3-4 large onions
pinch saffron
salt and pepper
2 eggs
3 tablespoons sour cream

Melt butter over low heat in cast iron or other heavy-bottomed pan.  Add thinly sliced onions and cook until soft, stirring occasionally, thirty minutes or longer.  Crush saffron threads and mix with a little hot water.  After onions have softened and the exuded liquid begins to evaporate, add the saffron and mix well.  Add salt and pepper.  When all the liquid is gone and the onions glisten with butter and feel thick, turn off burner and remove from heat and allow to cool. If you're in a hurry, put in refrigerator (or out the back door, if it's October in Minnesota!)

Preheat oven to 375°F.
Sprinkle flour onto your rolling surface and flatten your dough a little.  When a ball of dough it first rolled out the edges sometimes begin to break and separate; I use my hands to keep the edges together and whole, the way a potter centers a new hunk of clay.  Roll the dough to fit the pan; I use a standard tart pan with a fluted edge and removable bottom.   Sprinkle the bottom of the pan with a little cornmeal and fit the dough into the pan.

Put cooled onion mixture into bowl and add 2 beaten eggs.  Mix well.  Add sour cream and mix in.  Pour/scrape onion mixture into tart pan, using fork to spread evenly.  Bake for about one hour, or until top begins to brown slightly.  The tart can be served at almost any temperature.  If served as part of a sit-down dinner, it can be served hot - forks will be needed.  As an appetizer or potluck contribution, serve at room temperature so it holds its shape and can be stacked up next to a good Minnesota hotdish or macaroni salad.