Lightly grease your baking pan with cooking spray or butter before placing the pie crust inside. Press the crust gently into the edges and trim any excess dough hanging over the sides. I like to poke a few small holes in the base to prevent bubbling while cooking.
Place the crust in the air fryer for a few minutes to slightly pre-cook it before adding the filling. This helps the bottom stay crisp instead of becoming soggy. Preheating the crust also improves the overall texture of the quiche.
In a large bowl, whisk together the eggs, milk, salt, black pepper, and garlic powder until smooth. Whisking well creates a light and fluffy texture after cooking. Make sure there are no streaks of egg left in the mixture.
Add the shredded cheese, chopped broccoli, and sliced mushrooms into the bowl. Stir everything gently so the ingredients are evenly distributed throughout the filling. Fresh ingredients always give the best flavor and texture.
Carefully pour the egg mixture into the prepared crust-lined pan. Spread the vegetables evenly so every slice gets a balanced amount of filling. Do not overfill the pan because the eggs will puff slightly during cooking.
Tap the pan gently on the counter to remove air bubbles from the mixture. This helps the quiche cook more evenly and gives it a smooth surface. Sprinkle a little extra cheese on top if you want a golden cheesy finish.
Preheat your air fryer to 350°F for a few minutes before cooking. Place the filled pan carefully into the air fryer basket. Cook the quiche for about 15 to 20 minutes until the center looks set and the top becomes lightly golden.
Check the quiche near the end of cooking because air fryer models can vary slightly. If the top browns too quickly, loosely cover it with foil. The quiche is done when the center no longer jiggles when gently shaken.
Remove the quiche carefully from the air fryer and let it cool for several minutes. Cooling helps the filling firm up, making slicing much easier. Cutting too early can cause the filling to fall apart.
Slice the quiche into wedges and serve warm. I usually add fresh herbs or extra cheese on top for a fresh and colorful finish. It tastes amazing for breakfast, brunch, or even a light dinner.