Beat the duck eggs in a bowl with salt.

Heat butter in a non-stick skillet over medium heat until melted.

Pour the eggs into the skillet, swirling to spread evenly. Cook for 2-3 minutes until the edges start to lift.

As the top surface of the eggs begins to set, use a spatula to fold the omelet in half.

Cook for another 2-3 minutes until fully set but still tender.

Slide the omelet onto a plate, and serve immediately