Lightly spray a small nonstick skillet with cooking oil spray (or lightly butter it); wipe away excess with paper towel.
Mix porcini salt, or fine sea salt, into beaten eggs.
Place skillet over medium heat; add beaten eggs.
Evenly distribute mushrooms and chives over egg mixture.
As eggs begin to cook and become firm, carefully tilt the pan, slightly, and swirl the egg around in the pan, close to the edge; alternate swirling and setting pan flat over the heat until almost completely cooked.
Distribute cheese evenly over top, then do the same with the turkey; remove from heat.
Immediately fold omelette in thirds or in half and transfer to plate.
Garnish as desired. (I like extra chives and maldon salt flakes.)