Heat the oven to 180°C and line a baking tray.
Combine all dry ingredients in a large mixing bowl and mix well.
Add the wet ingredients to form the slightly sticky oatcake mixture.
Use fine oatmeal to lightly flour your work surface to prevent the dough from sticking, then flatten the dough with your hand before rolling it to approx. 4 mm thickness with a floured rolling pin.
Using a cookie cutter (I used a 7.5 mm cutter), cut out rounds of even thickness and carefully lift each oatcake onto a baking tray lined with baking paper. I use a dough scraper to help with the lifting.
If you have to bake the oatcakes in batches, make sure you mix together the leftover dough (use a tiny bit of extra water if it's gone a bit dry), storing it in a covered plastic bowl to prevent it from drying out while the other batch is baking.
Bake for 20 minutes, then carefully turn the oatcakes over and bake for 5 or 10 more minutes on the other side until they feel hard and dry on both sides. Prevent the oatcakes' edges from catching by moving them around a bit after 10 minutes.
Gently transfer to a wire rack to cool.
The oatcakes are delicious and tender but sturdy enough for any topping!