Mushroom and leek quiche

In terms of sustainability, eggs are one of the good guys—even better if you can afford a couple extra bucks to buy them from humane purveyors. That’s particularly true when you look at other protein sources in the dairy aisle: Producing 100 grams of protein in huevo form nets 4.21 kilos of greenhouse gases, compared with 9.5 kilos for an equivalent in milk and 10.8 for that in cheese. Sadly though, together with dairy, eggs are also among the most-wasted foods in U.S. kitchens. (It certainly doesn’t help that the dates on cartons are confusing AF.) 

But there are plenty of ways to use up your egg-cess. Today, we have our eyes on a dairy free and low-waste pie that uses six whole eggs and is a dumping ground for whatever leftovers are in your fridge. And no, you don’t have to make the crust from scratch, because Marie Callender’s frozen crust is buttery tasting (without butter) and flaky.

Quiche may be an obvious choice if you’re trying to use up eggs, but how do you make the custard base without heavy cream? Sure, you could simply swap it for a plant-based milk, but your filling won’t be quite as luxurious. To solve this quiche conundrum, our spin includes a quick plant-based bechamel to help set up the filling for smooth and silky success. First we make a roux, a cooked mixture of flour and nondairy butter, before whisking in oat milk and our fave faux-cheesy addition, nutritional yeast. 

As for the veggies, our go-to combo is mushroom and leek, but also think of quiche as a vehicle for any veggies or leftovers you need to get rid of. Some roasted broccoli or even cooked potatoes would be eggcellent (again, not sorry) here.

Mushroom and Leek Quiche

Yield: 6 to 8 slices 

Ingredients:

• 1 frozen deep-dish pie crust, defrosted for 15 minutes
• 5 tablespoons plant butter (like Miyoko’s brand), divided
• 1 large leek (greens and whites), halved and washed
• 10 ounces mixed mushrooms, such as oyster, shiitake, and cremini, sliced
• 2 teaspoons fresh thyme, chopped
• 1 teaspoon kosher salt
• 1 teaspoon black pepper
• 3 cups baby spinach, loosely packed 
• 2 tablespoons all-purpose flour
• 1 cup oat milk, divided
• 6 large eggs
• ½ cup nutritional yeast

Procedure:

1. Preheat the oven to 375 degrees. Prick bottom and sides of pie crust with a fork, and place it on a baking sheet. Bake for 10 minutes or until lightly browned. 
2. Meanwhile, in a large skillet, melt 2 tablespoons of butter over medium heat. Add the leeks, mushrooms, thyme, and ½ teaspoon each of salt and pepper. Cook until leeks are soft and mushrooms are tender, 8 to 10 minutes. Remove the pan from the heat and stir in the spinach to wilt. 
3. Transfer mushroom mixture to a bowl, give the skillet a quick wipe, and return to medium-low heat.  
4. Make the bechamel. Melt the remaining 3 tablespoons of butter and sprinkle in the flour, whisking continuously to prevent lumps. Whisk for 2 minutes, then reduce heat to low. Slowly whisk in ¾ cup oat milk until the mixture thickens, 1 to 2 minutes. Remove from heat and season with 1⁄4 teaspoon each salt and pepper.
5. Transfer bechamel to a large bowl and whisk in remaining ¼ cup oat milk. Add eggs, nutritional yeast, and ¼ teaspoon each salt and pepper, and whisk to combine. Pour half of the egg mixture into the pie crust, then sprinkle in half of the mushroom mixture. Repeat once more.
6. Pour filling into parbaked crust. Return to the oven and bake until the filling is just set (it will still jiggle a little in the center) and the crust is golden brown, 40 to 45 minutes. If the crust is browning too fast, you can cover the edges with aluminum foil. 
7. Let rest for 20 minutes before slicing. 

Notes and Substitutions: 

• No mushrooms or leeks? Replace with 1 ½ cups of whatever veggies you’ve got. Similarly, the spinach can be subbed with any leafy greens.
• Sub any plant-based milk for the oat, as long as it’s unflavored.
• If you’re feeling ambitious, here’s our from-scratch pie crust.