Step 1

Cut 1 tablespoon unsalted butter into two pieces. Melt one piece in an 8-inch nonstick frying pan over medium heat. Meanwhile, place 2 large eggs, 1/8 teaspoon kosher salt, and a grind of black pepper if desired in a small bowl and whisk with a fork until very well blended but not frothy.

Step 2

Add 1 cup baby spinach and a pinch of kosher salt to the pan. Cook, stirring occasionally, until completely wilted, about 1 minute. Transfer to a small plate or bowl.

Step 3

Add the remaining piece of butter to the pan (no need to wipe out) and return to medium heat. Tilt the pan to coat the bottom with butter. When the butter stops sizzling, pour in the eggs. Cook, gently moving the egg around constantly with a flexible, heat-resistant spatula, until curds just begin to form.

Step 4

Using the spatula and working your way around the pan, lift up sections of the cooked egg while tilting the pan to encourage the uncooked eggs to flow underneath. Try to keep the eggs in an even layer in the pan the whole time. Cook until the top is still wet but there is no flowing liquid egg left, 1 to 1 1/2 minutes total cooking time from when the eggs first went in the pan.

Step 5

Remove the pan from the heat. Sprinkle 1 tablespoon grated Parmesan cheese onto half of the omelet. Top the cheese evenly with the spinach. Run the spatula gently under the other half of the omelet to loosen and fold it over the spinach and cheese. Slide the omelet onto a plate.