Heat the oil in a large pan on medium heat. Add the chopped onion, parsnip, and carrot and cook for 8-10 minutes or until starting to soften, stirring regularly. Season with salt and pepper.
Add the mushrooms and garlic and cook for a few minutes until these start to soften.
Next, add the chopped jackfruit pieces. These will soften as the stew cooks, but you can also break some of the chunks apart with a spoon at this stage.
Add the potatoes and cook for a couple of minutes, stirring well. If using red wine, also add this and allow to cook down slightly.
Stir in the tomato puree, yeast extract, wholegrain mustard, dried herbs, smoked paprika, and bay leaves. Mix well.
Pour in the vegan stock, cover with a lid, and bring to a gentle simmer. Once simmering, continue to cook for 15-20 minutes or until the potatoes are soft enough to pierce with a knife. Stir every now and then, adding extra stock or water if necessary.
In a bowl or mug, combine the cornflour with a similar amount of cold water to create a slurry. Mix thoroughly to remove any lumps, then stir this into the stew and cook for a few minutes to thicken.
For a thicker stew, repeat the step above with one or two more tablespoons of cornflour. If you like, you can also break apart the jackfruit pieces using a spoon or fork.
Once the potatoes are soft, adjust the seasoning to taste and serve with chopped fresh parsley and a splash of vegan Worcestershire sauce.