June 13, 2020

Vegan French Onion Tart (Vegan Quiche)

This French onion tart is a perfectly satisfying supper, served with a simple side salad and maybe a little wine. The sweet and savory onions are plentiful in the soft and moist custard filling, all baked in a flaky, golden pie crust. This simple vegan quiche can be made year round, enjoyed warm or cool, and is just as delicious for breakfast is it is for supper.

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Tart or a Vegan Quiche?

I’m calling this a vegan French Onion Tart because I think it sounds better, but it’s basically the same idea as a quiche. Both have a flaky pie crust, both have a custardy, eggy filling. While tarts can be sweet or savory, and sometimes have a custard filling but sometimes don’t, quiches are always savory and always have a custard filling. I think if you were drawing a Venn diagram, all of quiches would be contained in the larger category of tarts, which might also all be contained in the larger category of pies. Long story short, call it a tart or a vegan quiche, or even a pie, but no matter what you’ll be calling it delicious!

Celebrating Alliums

Dork that I am, I recently wrote a short essay celebrating onions. For fun, no current plans to publish it. Just wanted to write about how great onions are. From peasants to pharrohs, onions have been adored throughout history from their delicious flavor and their health properties. Onions are part of the Allium genus, which also includes garlic, leeks, shallots, scallions, and more. Onions contain a lot of vitamin C, B vitamins, and potassium. They also contain a lot of the flavonoid quercetin, which can help prevent heart disease. The list of onion’s health benefits could continue, but I’m much more concerned with their food benefits. You’ll find onions as one of the first ingredients in just about every savory recipe, but not enough of them use Alliums as the star ingredient. That’s why we made this tart- to celebrate the pungent, sweet, flavorsome, and layered deliciousness of the onion.

To quote Julia Child, “It’s hard to imagine civilization without onions.”

Looking for Allium Recipes? Try one of these!

Making this French Onion Tart

Making this amazingly delicious vegan French onion tart involves three components- the crust, the onions, and the “custard”. I made my own pie crust, but if you want to save on time you can always go out to the store and find a pre-made vegan crust. If you are making your own, you can make it the day before if you like, or the day of as long as it has 20 minutes or so to chill in the fridge. We “blind-baked” (or cooked without the filling) our crust for a few minutes to help prevent the crust from getting soggy once the custard is added in.

The next bit is the onions- and this tart uses a lot of onion! It is a French Onion Tart, after all. Chopping the onions is by far the most painful part of the process- cutting onions will releases unstable sulfur compounds into the air, which is what brings on the tears. Your best defense for that is a good sharp knife. The onions are cooked for about 25 minutes before going into the tart shell, first on their own to sweat, and then with some garlic, mushrooms, and herbs de province. You want to try and get the onions perfectly soft, and ideally a little caramelized.

The final component that comes together to make our crust is the “custard” filling. This is a mix of silken tofu, chickpea flour, and other creamy, cheesy, flavors all blended together. When it cooks, the chickpea flour will firm up while the silken tofu keeps it soft, resulting in a soft yet stable filling. The final step is just adding all these components together- mix the onions and the custard, and pour into the par-baked pie crust. Stick it in the oven and let it bake away. Once it’s cooked, let it cool down to help it firm up, and you’re ready to eat!

Vegan French Onion Tart (Vegan Quiche)

Prep Time: 30 minutes

Cook Time: 35 minutes

Total Time: 1 hour, 10 minutes

Yield: 1 9-inch tart

Vegan French Onion Tart (Vegan Quiche)

Ingredients

For the Crust

1 ½ cups all-purpose flour
½ tsp. salt
½ cup vegan margarine

For the Filling

2 tbsp. vegan margarine or olive oil
1 tsp. salt, divided
3 medium-large onions (1 1/2-2 lbs.)
3 cloves garlic
¼ cup finely chopped oyster mushrooms
1 tbsp. herbs de province
8 oz. silken tofu
¼ cup nutritional yeast
1 tsp. Dijon mustard
1 cup Chickpea flour
¼ tsp. ground nutmeg
1-2 tbsp. grated vegan parmesan, optional

Instructions

First make your pie crust (if you like, you can also skip this section and use a premade crust). Combine the flour and salt, and whisk. Next add the vegan margarine in 1 tbsp. pieces, and use a fork or pastry cutter to cut the butter into the flour. Once you have an almost sandy texture, add water 1 tbsp. at a time (3-5 tbsp. total) until it forms a flaky dough. Form the dough into a disk, wrap in plastic wrap, and keep cool in the fridge for 20 minutes or more. After the dough has been chilled, place between two layers of plastic and roll out until it covers the bottom and sides of a 9-inch pie dish. Store in the fridge until ready to bake.
Preheat the oven to 375°F (190°C). Once it has preheated, place the pie crust and blind bake for 10 minutes (you can use beans or baking beads to make sure the crust holds its shape, but I typically just bake the empty shell). While you’re waiting for the oven to preheat, start on the filling.
Chop the onions in half-moons, mince the garlic, and mince the mushrooms. Heat the vegan margarine in a large skillet, and add the onions along with ½ tsp. of salt. Cook covered on a medium heat, stirring occasionally, for about 10 minutes. Then add the garlic, mushrooms, and herbs de province, and raise the heat to a medium-high. Cook for another 10-15 minutes, stirring occasionally, until some of the onions have developed a little caramelization. Turn off the heat and set aside.
Start on the “custard” part of the filling- in a blender, place the silken tofu, nutritional yeast, mustard, chickpea flour, nutmeg, remaining ½ tsp. of salt and ½ cup of water. Blend until smooth. In a large bowl, place the custard and the onions, and mix.
After the crust has blind baked, fill to the top with the custard and onions and return to the oven. Bake for 30-35 minutes. If you like, you can then grate vegan parmesan on the top of the tart, and place under the broiler on high for 3-5 minutes until golden. Allow to cool before serving, if you like. The more it cools, the firmer the texture of the filling will be.