Mushroom, Onion & Gruyere Quiche with Oat Crust

By amybites

290 cal, 16g fat, 7g sat fat, 24g carb 135mg cholesterol, 2g fiber, 410mg sodium

Ingredients

• For the crust:
• 3/4 cup old-fashioned oats
• 1/2 cup flour
• 1/4 teaspoon salt
• 3 tablespoons cold unsalted butter, cut into small pieces
• 3 tablespoons cold low fat buttermilk
• Nonstick cooking spray
• For the filling:
• 4 teaspoons olive oil
• 1 medium onion, thinly sliced into half moons
• 4 oz. mixed mushrooms such as cremini, oyster, shiitake, coarsely chopped
• 1/2 teaspoon salt
• 1/4 teaspoon pepper
• 1/4 teaspoon dry mustard
• 1 tablespoon chopped fresh thyme, or 1 teaspoon dried
• 1 1/2 cups cold low fat milk
• 3 tablespoons flour
• 3 large eggs
• 2 large egg whites
• 3/4 cup grated gruyere cheese (2 oz)

Preparation

Step 1

To make the crust, place the oats, flour, and salt in a food processor and pulse to combine. Add the butter and pulse about 12 times, until the mixture has a pebbly coarse texture. Add the buttermilk and pulse 3 to 5 more times to combine. Shape the dough into a flat disk, wrap it in a large piece of wax paper, and chill at least 1 hour and up to 2 days in advance.

When ready to bake, preheat the oven to 400ºF and spray a 9-in pie plate with cooking spray.

Roll the dough out to an 11-inch circle. Transfer the crust to the pie dish and press gently into the dish. Bake for 9 minutes, remove from the oven, and allow to cool. Reduce the oven temperature to 350ºF.

To make the filling, heat 2 teaspoons of the oil in a large nonstick pan over medium heat. Add the onion and cook, stirring occasionally, until softened, about 6 minutes. Reduce the heat to medium low, cover, and cook, stirring occasionally, until the onion is golden brown and caramelized, about 20 minutes more. Transfer the onion to a bowl. Add the remaining 2 teapsoons of oil to the pan and heat over medium-high heat. Add the mushrooms and cook, stirring occasionally, until they have released their water and begun to brown, about 6 minutes. Add the onion back to the pan and stir in the salt, black pepper, mustard, and thyme.

In a medium bowl, whisk together the milk and flour until the flour is dissolved. Add the eggs and whites and whisk until well combined.

Sprinkle the cheese into the pie crust. Top with the mushroom-onion mixture. Pour the egg mixture on top. Bake until a knife comes out clean, 45 to 50 minutes. Allow to cool for 5 minutes before cutting into 6 wedges and serving.