Chef's Notes
Don’t throw out left over dough. It will lose a bit of flakiness because it has been handled, but it’s still ok to use. Use it over the next couple of days, or freeze it for up to one month.
To blind-bake a pie or tart shell means to bake it without a filling. This step will ensure the crust is properly cooked when the pie or tart is done.
Making and Rolling the Dough
Make sure all of your ingredients are cold before making the dough. Add the salt to the flour and grate in the butter. Coat the butter with the flour by lightly tossing. Add the water, a bit at a time to form the dough. Lightly bring the dough together. Wrap and let rest in the refrigerator for approximately 45 minutes.
Roll the dough out to 1/4" -inch thickness. Transfer to a 9" -inch tart pan. Shape and place into the freezer for 20-30 minutes (or chill in the fridge for about an hour) until firm.
Step 1: Making and Rolling the Dough
- 5 tbsp ice cold water
- 1 2/3 cups all-purpose flour
- 1 pinch table salt
- 10 tbsp cold, unsalted butter
Preparing the Onions & Pre-Baking Tart
Preheat your oven to 425° degrees Fahrenheit.
Thinly slice the onions. Heat a large fry pan over high heat. Add the oil and onions and then reduce the heat to medium. Cover and let sweat for about 5 to 10 minutes, or until soft and melted. Remove the lid and let this cook for another 15 minutes or so, stirring occasionally. Once all of the moisture has evaporated, caramelization will occur rather quickly. Add the salt and make sure to stir every 20 seconds or so to obtain even coloring.
Off the heat, deglaze with a bit of water, and scrape to clean the bottom of the pan. Sprinkle in the flour and then add the milk. Stir to combine. Season with the salt and white pepper and set aside to cool.
Poke holes into the dough (this is called ‘docking’) and blind-bake the shell until cooked through.
Step 2: Preparing the Onions & Pre-Baking Tart
- 7 cups onions
- 1/4 cup vegetable oil
- 2 pinches table salt
- 2 tbsp all-purpose flour
- 1/2 cup milk
- 1/2 tsp table salt
- 1/8 tsp white pepper
Baking the Tart
To finish the tart, turn the heat down to 350° degrees Fahrenheit. Taste the mixture for seasoning. Place it into the tart shell and spread it out evenly.
Bake for approximately 15 minutes, or until the top sets and the filling binds with the sides of the dough. Let cool for a few minutes before removing from the pan. Slice and serve.