Preheat your oven to 350°F and generously grease a 12-cup muffin tin with olive oil or line with silicone muffin cups.
Grate the zucchini and place it in a clean kitchen towel, then squeeze firmly over the sink to remove as much liquid as possible.
In a large mixing bowl, whisk together the eggs, heavy cream, garlic powder, salt, and black pepper until well combined.
Stir in the squeezed-dry zucchini, shredded cheddar cheese, diced bell peppers, and diced onion until evenly distributed.
Pour the egg mixture evenly into the prepared muffin cups, filling each about three-quarters full.
Bake for 22-25 minutes until the muffins are set in the center and lightly golden on top.
Allow to cool in the pan for 5 minutes before removing and serving warm, or store in an airtight container in the refrigerator for up to 5 days.