Heat the oven to 240C/fan 220C/gas 9. Put 1½ tsp of oil into each of five of the holes of a deep six-hole muffin tin. Swirl the tin to make sure the sides of each hole are oiled. Put onto a sturdy metal baking sheet and into the top of the oven for 15 minutes.
Put all of the remaining ingredients into a high-speed blender along with 125ml of water. Blend until completely smooth.
After 15 minutes, carefully remove the tin and baking sheet from the oven. Working quickly, pour the batter in a thin, constant stream, evenly filling the five holes (pour the batter in a circular motion onto the sides of the holes – this traps a little well of oil in the centre which helps to form the hole in the middle). Swiftly return the tin to the oven.
Bake for 20 minutes, then remove the tin from the oven. Carefully remove each pudding and put on a separate baking tray. Return the yorkshires to the oven for a further 5 minutes to crisp up. Remove from the oven and sit for 5 minutes (this will let the steam evaporate, resulting in a crispier pudding). Serve with your favourite vegan roast, veg and gravy, if you like.