In a large bowl, whisk together flour, water, eggs, and salt until you have a thin, smooth batter.

Heat a non-stick skillet over medium-low heat and lightly coat with cooking spray.

Pour about 1/4 cup of batter into the skillet, tilting the pan to spread the batter thinly across the surface.

Cook until the top of the batter sets and the edges start to look dry, about 1-2 minutes.

Carefully flip the shell using a spatula and cook for an additional 10-20 seconds.

Transfer the cooked shell to a plate and repeat with the remaining batter.