Put the egg, oats, hazelnut milk and hazelnuts in a blender and whiz until you get a thick, smooth batter. Add more milk if it's too thick. Stir in the cinnamon, baking powder and oil.
If time allows, rest the batter for 15 minutes.
Heat a lightly oiled pancake griddle, then add dollops of the batter, spreading them into circle shapes (or you can use silicon pancake moulds).
Cook for a minute or so, until the surface has almost set, then flip them over and cook for another minute or so on the other side, until golden.
Transfer them to a plate and repeat with the remaining batter.
Serve at room temperature with chopped hazelnuts, maple syrup or chocolate sauce.