Preheat the oven to 375 degrees F. Coat a 9-inch pie dish with cooking spray.
Place the pancetta in a large nonstick skillet set over medium heat. Cook until the pancetta is crisp, about 8 minutes. Transfer the pancetta to a paper towel to drain. Discard the fat from the skillet and wipe the skillet with a paper towel.
Place the nonstick skillet over medium-high heat and add the olive oil. Add the mushrooms and cook until tender, 3 to 4 minutes. Stir in the fresh thyme and cook for 1 minute.
In a large bowl, whisk together the eggs, egg whites, water, smoked paprika, salt and pepper. Pour the egg mixture into the prepared pie dish.
Sprinkle the pancetta and mushroom mixture evenly over the eggs.
Baked until the egg is set in the center and starting to brown, about 25 minutes.
Let the quiche cool for about 10 minutes, garnish with parsley and cut into 6 wedges. Serve.