In a small pan, heat the butter over low heat until it melts. Set it aside. Place the flour, eggs, milk, sugar, salt and melted butter in the blender and purée until smooth, for about 10 seconds. Add water and blend again until smooth. You can also mix the ingredients by hand, following the same order.
Place the batter in a container, cover and refrigerate for at least half an hour, or up to a couple days. Once ready to make the crepes, whisk the batter well with a fork or a whisk, or shake it in the sealed container.
Set a crepe pan or non-stick skillet over medium heat for a couple of minutes. Butter the bottom of the pan and ladle about 1/4 cup of batter onto it. Instead of working from the center to the sides, tilt the pan and pour the batter over one side and spread it as quickly as possible over the rest of the pan, so that it covers the entire surface.
Cook for about 20 to 25 seconds, until edges are cooked and begin to dry out and the bottom of the crepe is lightly browned. With a small spatula or fork, lift one edge of the crepe and turn it over quickly with your fingers. Cook the second side for about 10 to 15 seconds, or until it has lightly browned. Flip the crepe onto a plate.
Repeat with the rest of the batter. After 3 or 4 crepes, you may need to butter the pan again. If it isn’t a nonstick pan, you may need to do it for every one. Stack the crepes on top of each other with the first, darker side down. That darker side will become the outer layer of the crepe, once you fill them up or fold them.
If you aren’t going to use all of the crepes at once, or if you are making them ahead of time, wrap them in plastic wrap and place them in a closed plastic bag. Store in the refrigerator up to 4 days or in the freezer for weeks.
NOTE: If making sweet crepes, I use this same recipe but use 2 tablespoons sugar instead of 1 teaspoon, and only a pinch of salt instead of 1/2 teaspoon.