Mix flour, water, egg in large bowl.
Add salt and pepper to batter.
Whisk until completely smooth and lump-free.
Heat oil in non-stick pan.
Pour half batter into heated pan.
Sprinkle cheese evenly over batter surface.
Add chopped green onions on top.
Pour remaining batter over cheese layer.
Cook for three minutes until bottom browns.
Flip pancake carefully using large spatula.
Cook another three minutes until golden.
Serve immediately while cheese is melted.