In a large mixing bowl, whisk together the flour and eggs until smooth.
Gradually add milk and water, stirring constantly to combine well.
Add salt and melted butter to the batter and beat until smooth and slightly thin.
Heat a lightly oiled griddle or non-stick frying pan over medium-high heat.
Pour approximately 1/4 cup of batter onto the griddle, tilting the pan in a circular motion to evenly coat the surface.
Cook the crepe for about 2 minutes or until the bottom is light golden brown. Loosen with a spatula, flip and cook the other side for about 1 minute. Remove and keep warm.
For the apple filling, heat a pan over medium heat and add the chopped apples.
Sprinkle cinnamon and brown sugar over the apples and stir continuously until the apples soften and caramelize, about 5-7 minutes.
Spoon the warm apple cinnamon filling onto each crepe, fold or roll as desired, and serve immediately.