Preheat the oven to 360℉ (180℃). Brush or spray a muffin tray generously with oil. Oiling it well will make sure the muffins will come out easily. Keep the tray aside.
Heat light olive oil in a pan over medium-high heat. Once the oil is hot, add garlic and fry for 5-6 seconds.
Add onions and mixed bell peppers and cook for 30 seconds.
Add mushrooms and spinach and cook for 4-5 minutes until the mixture is dry.
Remove the pan from the heat and let the veggies cool down for 5 minutes.
Now add the cooked veggies to 10-12 egg whites and mix well.
Note – Mixing the egg whites and vegetables in a measuring cup will make the pouring easier.
Add salt, sriracha sauce, and black pepper, and mix well.
Pour the egg mixture into the cavities of the prepared muffin tin until ¾th full.
Keep the tray in the middle rack of the oven and bake for 20-25 minutes until the egg whites are set. Remove the tray from the oven and let the muffins cool down for 5 minutes.
Once the eggs are cooled and perfectly set, just slide a spoon or a butter knife on the side and push the egg muffins upwards. They will slide out easily. Serve hot.
Grease the tray well before pouring the egg mixture into it. We don't want the muffins to stick to the tray after they are baked.You can line the tray cavities with paper liners to handle muffins easily.I used room-temperature egg whites, but if you use them directly from the temperature, increase the baking time by a minute or 2.Cut the veggies into small, even pieces.You can double or half this recipe as required.You can freeze the muffins and reheat them in the microwave when required.