In a large mixing bowl, whisk the eggs with the flour and salt and gradually mix in the milk. Mix until smooth.
Lightly butter the heated non-stick fry pan. Pour a laddle or less of batter into the heated pan and spread out the batter in a circular motion so that batter coats the pan evenly.
Keep the fire medium-low so that the batter cooks evenly without burns. In the mean time, put in some chopped english spinach and crumbled the ricotta cheese onto the batter.
Quickly, use your hand and spatula, fold the crepe into envelope shape and turn over other side. Cook for another 2 minutes or until the cheese melted. Serve hot.