Caramelized Onion, Mushroom and Gruyere Quiche with Oat Crust - Fair Shares

Ingredients

• Cooking spray
• 3/4 cup rolled oats
• 1/2 cup all-purpose flour
• 1/4 teaspoon salt
• 3 tablespoons cold, unsalted butter, cut into small pieces
• 3 tablespoons cold, lowfat buttermilk
• 4 teaspoons olive oil
• 1 large onion, sliced thinly into half moons
• 8 ounces sliced mixed mushrooms, such as cremini, oyster, shiitake
• 1/2 teaspoon salt
• 1/4 teaspoon freshly ground black pepper
• 1/4 teaspoon dry mustard
• 1 tablespoon chopped fresh thyme leaves (or 1 teaspoon dry)
• 4 large eggs
• 1/2 cup evaporated fat-free milk (not condensed milk)
• 2/3 cup grated Gruyere cheese