In a small nonstick skillet, saute the apple, sugar and cinnamon in 1 tablespoon butter. Remove from skillet and set aside.
In the same skillet, melt remaining butter over medium-high heat. Whisk the eggs, water, salt and pepper. Add egg mixture to skillet (mixture should set immediately at edges).
As eggs set, push cooked edges toward the center, letting uncooked portion flow underneath. When the eggs are set, spoon apple mixture on one side; fold other side over filling. Slide omelet onto a plate. Serve with whipped cream.