Alsace Onion Tart
In traditional recipes from Alsace such as this one, you cook the onions with smoked bacon and mix them with Béchamel sauce before baking, not to be confused with an onion quiche also sometimes called Onion Tart.
Servings: 8
Ingredients
SHORT CRUST PASTRY:
- 8 ounces all-purpose flour
- 4 ounces butter
- 0.25 teaspoon salt
- 1 large egg
- A few drops cold water
FOR THE ONIONS:
- 2 ounces butter
- 0.25 pound smoked bacon
- 2 medium onions, sliced finely
- 0.5 teaspoon dried thyme
- 2 medium bay leaves
- Salt and freshly ground pepper
FOR THE BÉCHAMEL:
- 2.5 tablespoons butter
- 3.5 tablespoons flour
- 2 cups cold milk
- 0.5 teaspoon salt and ground white pepper to taste
- Pinch of nutmeg
- 3 eggs
Instructions
- Pre-heat the oven, and a baking sheet, to gas mark 4, 350°F (180°C). You will also need an 8 inch (20 cm) fluted ceramic tart tin, greased.
- Cook the onions: Melt the butter in a heavy-based saucepan, then add the bacon, chopped onions, thyme, bay leaves, salt and pepper, stir to get them well coated in the butter, and cook them uncovered over a medium heat for about half an hour until they have reduced and are fully cooked. Give them a stir from time to time to prevent them from catching on the bottom of the pan and if they do, add few drops of water to burning. When the onions are fully cooked, strain them into a colander and remove bay leaves.
- Short-crust pastry: Make the dough using a food processor. Combine the first three ingredients until the butter is smooth. While the machine is running, add the egg through the feeding tube, then add a few drops of cold water and stop processing as soon as the dough becomes a ball. Do not overwork the dough. Remove the dough and wrap it in plastic wrap. Refrigerate for at least 30 minutes.
- To make Béchamel sauce: Melt the butter in a saucepan. Whisk in the flour to create a smooth, loose paste. Stir over moderate heat, allowing the butter and flour to cook for approximately 2 minutes without changing color from a buttery yellow. Add half of the milk, whisking vigorously to thoroughly blend. Then whisk more slowly over a heat, scraping the bottom and sides of the pan and add the remaining milk. Season with salt, pepper, and nutmeg. Bring to a boil for few seconds and remove from the heat. The sauce should be thick enough to coat a spoon.
- Cook the tart: Add the drained onions to the Béchamel and mix well. Taste and rectify the seasoning if necessary. Break the egg one by one, add them to the mixture and mix until well blended. Then roll out the pastry to line the tart tin and spread the onions all over the base of the tart, and bake the French onion tart for 45 to 55 minutes or until the filling is puffy and golden brown and fully cooked. Remove from oven and place the French onion tart on a cooling rack for about 30 minutes before unmolding and cutting.