Heat a non-stick frying pan (preferably the one used to make the crêpes) over medium-low heat. Place 1 crêpe on the pan and sprinkle with 1/2 of the cheese.
Place the 2nd piece of crêpe on top and sprinkle the edges with the remaining cheese (the cheese will act as a glue later on when you fold in the crêpe.)
Crack the egg in the middle and season with salt and black pepper (if your cheese is the salty kind, use less salt).
Cover the pan with a lid or a larger plate and cook over medium-low heat for 2 to 3 minutes, until the egg whites are cooked but the yolk is still runny and the cheese has melted.
Sprinkle the spring onion and chives on top, fold in four sides of the crêpes to form a square and slide it out onto a serving plate. Serve immediately.
NOTES
You can use one crêpe instead of two to make this, just that you will lose the chewy crêpe texture as the bottom crêpe will become crispy.
You can add ham, smoked salmon, canned tuna, sautéed mushrooms, sautéed spinach etc on top of the 2nd crêpe before cracking the egg on top for a meat-version. Don't overfill the crêpe or you may have trouble forming a square. If you have seasoned the filling beforehand, cut down on the salt.