1. Whisk eggs, water, salt, and pepper in bowl until blended.
2. Melt butter in 10-inch nonstick skillet over medium heat.
3. Pout in egg mixture. Cook 1 minute, until omelet starts to set. With spatula, push back cooked egg. Cook 1 to 2 minutes more, until top is set. With handle of skillet facing you, spoon 1/2 cup desired filling down one side of omelet.
4. Run knife around edge of egg. (Don't worry if edges tear; when omelet is folded over, you won't see it.) roll omelet over filling and slip onto plate, flipping to encase the filling.
5. Repeat steps 1 through 4 three more times, for more omelets.Spinach with Fontina Filling::
6. Heat 1 tablespoon butter in skillet over medium heat. Add 1/2 cup chopped onion and cook, stirring, until lightly browned. Chop 2 bags (10 oz. each) fresh spinach. Add half the spinach to skillet with 1/2 teaspoon salt and 1/4 teaspoon pepper; cover and cook 2 minutes, until wilted. Stir in remaining spinach, cover and cook 2 minutes more. Drain spinach; transfer to bowl and stir in 1/4 pound diced Fontina cheese. Makes 2 cups.
7. Nutritional Information per omelet: 415 calories, 33.5 g. total fat, 17.5 g saturated fat, 497 mg cholesterol, 1,160 mg sodium, 7 g carbohydrates, 23 g proteinHam with Cheddar Filling::
8. Heat 1 tablespoon butter in skillet over medium-high heat. Add 2 tablespoons minced shallots and cook, stirring, 1 minute. Stir in 1/2 pound smoked ham, chopped, 1/2 teaspoon chopped fresh thyme or pinch dried, and pinch pepper. Reduce heat to medium and cook until lightly browned. Transfer to bowl; stir in 1 cup shredded sharp Cheddar cheese. Makes 2 cups.
9. Nutritional Information per omelette: 355 calories, 27 g total fat, 13 g saturated fat, 490 mg cholesterol, 1,373 mg sodium, 3 g carbohydrates, 24 g proteinMushroom with Goat Cheese Filling::
10. Heat 1 tablespoon butter in skillet over medium-high heat. Add 1 pound white mushrooms, sliced, 2 tablespoons minced shallots, 1/2 teaspoon salt, and 1/4 teaspoon freshly ground pepper. Cook, stirring, 6 to 7 minutes, until browned. Stir in 1 tablespoon chopped fresh tarragon or 1/2 teaspoon dried; cook 30 seconds. Transfer to bowl. Add 2 ounces fresh goat cheese, crumbled. Makes 2 cups.
11. Nutrition Information per omelette: 345 calories, 28 g total fat, 14 g saturated fat, 470 mg cholesterol, 909 mg sodium, 8 mg carbohydrates, 18 g protein.