In a blender or large bowl, combine low-fat milk, water, all-purpose flour, eggs, melted light butter, and salt. If desired, add vanilla extract. Blend or whisk until smooth. Let rest for 5–10 minutes.

Preheat a nonstick skillet over medium heat and lightly grease it with cooking spray or butter.

Pour ¼ cup of batter into the hot pan, tilting to spread evenly. Cook for 1–2 minutes until the bottom is lightly golden, then flip and cook for 30–60 seconds more. Transfer to a plate.

Stack cooked crepes and cover with foil to keep warm while finishing the rest.

Fill each crepe with your favorite fillings and serve warm.