Add 2 tablespoonsunsalted butter. Oncebutter sizzles andbegins to brown, swirlto coat pan.
Add3 beaten eggs andseason with koshersalt and freshlyground black pepper.Cook, pulling up theedges with a heatproofsilicone spatula,allowing uncookedeggs to run into pan,until the bottom isgolden brown andthe top begins to set,1-2 minutes.
Add fillings, suchas caramelized onions,chopped herbs, andgrated Parmesan.Using the spatula, foldup 1/3 of the omelet.
Roll the omelet overonto itself, then tilt thepan and slide omeletonto a plate.