Gather all ingredients. Preheat the oven to 350 degrees F (175 degrees C). Grease a 12-cup muffin tin with cooking spray.

Place bell peppers and green onions into a large bowl.

Add eggs, bacon, milk, garlic powder, onion powder, salt, and pepper.

Sprinkle Cheddar cheese into the bowl and whisk until incorporated.

Pour mixture equally into the prepared muffin cups.

Bake in the preheated oven until a toothpick inserted into the center of a muffin comes out clean, about 30 minutes. Let cool slightly before serving.