A fluffy Denver omelet stuffed with ham, peppers, onions, and cheese is a hearty, high protein American breakfast classic. This family-friendly omelet is a diner favorite that's easy to make at home.
In a medium bowl, whisk together the eggs with salt and black pepper until well-blended and slightly frothy—this helps the omelet rise.
Heat half the butter (1/2 tbsp) in a nonstick 10-inch skillet over medium heat. Add the diced ham, green bell pepper, and onion. Sauté for 4 minutes, stirring occasionally, until the vegetables are softened and ham starts to brown.
Transfer the sautéed mixture to a bowl. Add the remaining butter to the pan and let it melt, then pour in the beaten eggs, tilting the pan so eggs coat the bottom evenly.
As the eggs begin to set around the edges (about 1 minute), gently lift the cooked edge with a spatula, allowing uncooked egg to flow underneath. Keep heat at medium-low to prevent browning the eggs.
When the center is still slightly soft but almost set, scatter the ham, pepper, and onion mixture over half the omelet. Sprinkle cheese evenly on top, cover with a lid, and let cook 30 seconds until the cheese melts.
Fold the omelet in half with the spatula, slide onto a plate, and serve immediately.