Preheat your oven to 375°F (190°C).

Grease a 9-inch pie dish with butter.

In a large bowl, whisk together eggs, milk, salt, and pepper until smooth.

Stir in ham, shredded cheddar, and diced onions.

Pour the mixture into the prepared pie dish.

Bake for 30–35 minutes, or until the center is set and the top turns golden.

Let cool for 5 minutes before slicing.