Beat together the egg and brown sugar with a whisk until light and fluffy. Add the vanilla and peanut butter. Mix well. Stir through the flour, oats and chocolate until combined. Roll the dough into balls and place on a greased baking tray. Press down to flatten with clean fingers. Bake at 170 degrees Celsius for 10 minutes or until cooked.
Enjoy the peanut butter chocolate cookies!