Add the water, fresh spinach, rolled oats, eggs, salt, black pepper and sunflower oil to a blender and blend until smooth.
Heat a lightly oiled non‑stick frying pan over medium heat.
Pour the green batter into the pan and spread it evenly like a large pancake.
Cook until the underside is golden and the edges are set, then flip carefully.
Place the shredded cheese on one half of the pancake.
Fold the pancake in half over the cheese and cook until both sides are golden and the cheese inside is melted.
Remove from the pan, let it rest briefly, then slice and serve warm.