Preheat your oven to 350°F (175°C). This ensures that the egg bites cook evenly and rise properly.

Spray a muffin tin with non-stick cooking spray to prevent the egg bites from sticking.

In a mixing bowl, crack 6 large eggs and add ¼ cup of milk, ½ teaspoon of salt, and ¼ teaspoon of black pepper.

Whisk the mixture until well combined and slightly frothy. This incorporates air into the eggs, making them fluffy.

Stir in your choice of add-ins: ½ cup of shredded cheddar cheese, ½ cup of finely diced bell pepper, ¼ cup of sliced green onions, ¼ cup of chopped spinach, and ½ cup of crumbled cooked bacon (if using).

Mix until all ingredients are evenly distributed throughout the egg mixture.

Pour the egg mixture evenly into the prepared muffin tin, filling each cup about ¾ full. This allows space for the egg bites to rise.

Bake in the preheated oven for 15-18 minutes, or until the egg bites are set and lightly golden on top. You can check for doneness by inserting a toothpick; it should come out clean.

Remove the muffin tin from the oven and allow the egg bites to cool for a few minutes before gently running a knife around the edges to loosen them.

Carefully remove the egg bites from the tin and serve warm. They can also be stored in an airtight container in the refrigerator for up to 5 days.