Grind the rolled oats into a fine flour and, if you wish, sift to remove any larger pieces.
Blend the spinach, coriander, water and garlic until smooth.
Pour the green mixture into the oat flour, add the salt and mix to form a dough.
Knead the dough with the olive oil until it becomes soft and smooth.
Divide the dough into six equal balls.
Lightly dust the work surface with oat flour and roll each ball into a thin flatbread.
Heat a dry pan over medium heat.
Cook each flatbread for a few minutes until bubbles form and the underside is lightly golden, then flip and cook the other side.
Brush the warm flatbreads lightly with butter if desired and serve.