In the cup of a high speed blender, combine the chickpeas (including their soaking water), the water, bouillon powder, white wine vinegar, onion powder, garlic powder and silken tofu. Blend until very smooth.
In the bowl of a stand mixer, fitted with the dough hook, combine the vital wheat gluten and the blended liquid. Knead on medium speed with the dough hook for no less that 5 minutes. The seitan dough should be smooth and stretchy.
Cover the mixing bowl and leave to rest for ten minutes.
Once rested, remove the dough from the mixer and slice into three even sized pieces. Return two of the pieces to the covered bowl. Take the one piece of dough and slice it into six separate pieces (don't worry if they're all different sizes – just roughly the same is fine).
Lay out a piece of baking parchment and take one of the small pieces of dough. Place the dough on the left hand side of the baking parchment, then fold over to cover the dough. With a rolling pin, roll out the dough as thinly as you can. Unfold the parchment and peel off the thin piece of seitan. Stretch it out with your fingers and place it flat on a plate. Brush it very lightly with vegetable oil.
Repeat the process with the next piece of dough – roll it out very thinly then remove from the parchment. Stretch it out with your fingertips and place it in top of the first piece, pushing down lightly with the flat of your hand to remove any air bubbles between the two pieces of seitan. Brush the top piece lightly with oil then repeat the process with the remaining small pieces of dough.
Once all six small pieces of dough are layered, stretch the top piece of dough down and over the other layers to envelop them and tuck under the bottom layer. Place the layered piece of seitan on a new large piece of baking parchment and fold it up tightly. Wrap tightly with tin foil and set aside.
Repeat the process with the other two large pieces of dough.
Bring a steamer to the boil and place all three pieces of seitan in the steamer. Steam for a total of 90 minutes, flipping and moving the pieces around half way.
Once the seitan is steamed, carefully remove it from the steamer and allow it to cool to room temperature (20 minutes) before placing in the fridge for at least an hour. Do not unwrap.
Once cooled fully, unwrap the seitan and tear apart into whatever size shreds you'd like. (If you're planning to make fried chicken, I'd suggest keeping the shreds quite large. If you're using in a curry, I'd go a bit smaller).
Keep sealed in the fridge for up to a week or in the freezer for 2 months.