Put the oats and ground linseeds in a small blender and pulse until you have a fine floury powder.
Add the oat milk powder (if using) and pulse again to mix.
If your blender takes liquid, you can add the apple puree and water and blend to mix in, otherwise, transfer to a jug and whisk in by hand.
Leave your mix to stand for a few minutes to naturally thicken.
Heat a non-stick pan (use a bit of oil if you need to) and pour or ladle a small amount of batter into the pan. Swirl the mixture around to spread it and level it out. Allow to cook until you see small holes appear and the batter begin to firm up.
If you want to make mini pancakes, use a teaspoon and dot 4 or 5 teaspoonfuls around the pan. When you turn them over, they will only need a few seconds on the other side.
Using a fish slice, flip the pancake over onto the other side, and allow to cook for a few minutes.
Remove from the pan and repeat with the remining batter. Either eat immediately or keep warm in the oven until needed.