• Place the walnuts in a medium sized bowl with warm water.
• Soak the walnuts for about 20 minutes, then drain and discard the water.
• Place the walnuts along with the mushrooms in a food processor fitted with an S blade.
• Pulse (using the on/off function) the walnuts until they break down into a "meat crumble" being careful not to overprocess.
• In a medium sized frying pan, heat the olive oil on medium heat.
• Saute the onion, garlic along with the walnut crumble and mushrooms until it is soft (this should take a few minutes).
• Add the chopped bell pepper, tomato and continue to cook for 2-3 minutes.
• Add the beef seasoning, thyme and chadon beni.
• Add the browning sauce, soy(a) sauce, tomato paste and vegetable broth then mix everything together.
• Cook the mixture for a further 8-10 minutes, stirring occasionally so it doesn't stick, you want the mixture to be moist, not wet and definitely not dry so adjust with a splash of water if needed.
• Do a taste test and add pink salt and black pepper if needed.

To assemble the taco

• Heat a large frying pan or skillet on medium-low heat.
• Coat the bottom of the pan very lightly with olive oil.
• Place the taco(s) in the frying pan (you may need to do this in batches).
• Add a generous amount of filling to one side of the taco and top with vegan cheese.
• Fold over the taco onto the filling, using an egg spatula and press down to secure the folded side.
• Cook the underside until slightly brown, once done flip the taco over and cook the other side until slightly brown.

For the oven version

• Preheat the oven to 180C/356F/gas mark 4.
• Line a baking tray with parchment paper.
• Lightly grease the parchment paper with oil.
• Place the tacos on the baking tray (mine could only hold 2 at a time, so do this in batches if necessary).
• Add a generous amount of filling to one side of the taco and top with vegan cheese.
• Fold the other side onto the cheese and press down with an egg spatula.
• Bake in the oven for around 10 minutes or until the taco is crunchy.