In a large mixing bowl, whisk together the flour and the eggs. Gradually add the milk and water, stirring to combine. Add the salt and butter and beat until smooth. Fold in the poblano puree.
Heat a lightly oiled griddle or skillet over medium-high heat. Using a one-ounce ladle, pour the batter for each crepe onto the griddle. Tilt the pan with a circular motion so that the batter coats the surface evenly. Cook for about 2 minutes, or until the bottom is light brown. Loosen with a spatula, turn, and cook the other side for the same amount of time.
Recipe courtesy of Ivy Stark, from her cookbook Dos Caminos: Mexican Street Food