I usually make this spinach-egg omelet. I use 2 eggs and a small amount of blanched spinach. I use 1 tbsp of whipped butter (this equates to a little over 1/2 a tbsp of stick butter) to grease the pan, and my omelet STILL sticks. I use a stainless steel pan (I don’t use nonstick/Teflon pans for personal health reasons). Oh yeah, and don’t recommend using cooking spray; I prefer not to coat my food in chemicals propellants.
Thanks to all who respond!