Preheat oven to 400°F (200°C). Line a 12-cup muffin pan with silicone liners or grease well.
In a large bowl, whisk eggs with salt and black pepper.
Add garlic powder and dried basil, whisk until combined.
Stir in chopped spinach and grated cheese.
Divide mixture evenly into muffin cups, filling each about ⅔ full.
Sprinkle extra cheese on top if desired.
Bake for 12–15 minutes, until the centers are set.
These spinach egg muffins with cheese should be lightly golden and firm when done.