For this omelette I fill it with prosciutto and Boursin cheese, then fold it into thirds and serve it with avocado and arugula. The prosciutto will provide a lot of salt, so use any additional salt carefully.
In a medium mixing bowl whisk the eggs until they fall off the whisk in ribbons.
Heat an 8-inch, nonstick skillet over medium heat. Add 1 tablespoon of butter and allow it to melt. Add the eggs and stir, using a rubber spatula making sure nothing sticks to the pan. Season with kosher salt then immediately start stirring and shaking the omelette, occasionally scraping the sides.
Once the eggs form ribbons shake the pan so that the uncooked eggs fill in the open spaces. Let the eggs sit for about a minute so that the bottom holds together and is set but the top is still slightly runny.
Add the Boursin cheese in a line down the center of the omelette. Add one of the slices of prosciutto down the middle then gently begin to fold the omelette.
Hold the pan by the handle and tilt the pan down to the side then gently begin to roll the omelette into thirds. Add an additional tablespoon of butter to the pan to help it release and fold.
Carefully transfer to a plate and brush with the remaining butter. Top with the remaining prosciutto, avocado, and arugula. Season with black pepper and garnish with the Parmesan. Serve immediately.