Preheat grill to high heat. Heat 30gm butter in a frying pan over medium heat, add leek, garlic and thyme and sauté until tender (4-5 minutes). Add wine and lemon rind, cook until evaporated (1-2 minutes), then transfer two-thirds of leek mixture to a bowl (reserve remaining). Add crème fraîche, yolks, flour and parsley, crumble in half the chèvre, season to taste and stir to combine.
Whisk eggwhites and a pinch of salt in a bowl until firm peaks form, then fold into yolk mixture.
Heat remaining butter in a 25cm-diameter frying pan over medium heat until foaming, add egg mixture, shaking pan gently to level. Cook until base is golden (1-2 minutes), scatter remaining leek mixture and chèvre over one half of the omelette, then grill until light golden (1-2 minutes). Carefully slide onto a warm serving plate, folding in half as you go. Serve hot with toasted baguette slices.
This recipe is from the July 2010 issue of Australian Gourmet Traveller.