Crack the eggs into a bowl and add milk, salt, pepper, and garlic powder. Whisk vigorously until the mixture is completely smooth and slightly frothy.

Heat a non-stick 8-inch pan over medium-low heat and add butter, swirling to coat the entire surface evenly.

Add the chopped spinach to the pan and cook for 30-45 seconds until just wilted, then remove and set aside.

Pour the beaten egg mixture into the same pan, allowing it to spread evenly across the bottom surface.

As the edges begin to set, gently lift them with a spatula and tilt the pan to let uncooked egg flow underneath.

When the eggs are almost set but still slightly wet on top, add the wilted spinach and shredded cheese to one half of the omelette.

Using a spatula, carefully fold the empty half over the filled half, creating a half-moon shape.

Slide the omelette onto a warmed plate and serve immediately while the cheese is still melted and creamy.