Preheat oven to 220C. Cover two sheet pans with parchment paper.
Spread half of the grated vegetables on a clean kitchen towel, then roll and squeeze the towel to draw out the excess moisture. Transfer to a large mixing bowl. Repeat with the remaining vegetables.
In a small bowl, combine the oat flour, baking powder, and pepper. Add to the vegetable bowl, and mix well, using your hands to evenly distribute the flour and baking powder.
Scoop about ¼ cup of potato mixture, and hand-shape it into a semi-tight ball. Flatten with your palms, and place the pancake onto the prepared pans. Repeat with the remaining mix, spacing the pancakes about 5 cm apart.
Bake for 12 minutes. Flip and bake for another 12 minutes, or to your desired level of crispness. Serve at once. Top with the condiment of your choice e.g. tahini!