Preheat oven to 350 degrees. Combine all dry ingredients in a large bowl and mix thoroughly. In a medium bowl or blender, combine all wet ingredients and then add them to the dry bowl. Add jackfruit shreds, stir thoroughly, and then begin to knead. Do so for a few minutes until you have a cohesive mass. You will lose a few jackfruit shreds, but no worries.
Wrap tightly in two large pieces of sturdy aluminum foil and bake for 1 hour. Meanwhile, prep your other pot roast ingredients. Prepare veggies by peeling potatoes and carrots (if you wanna), then roughly chopping them and the onion into bite sized cubes. Add to the dutch oven with butter and heat on medium for 3 minutes. Add sauce ingredients to a blender to combine, then put them in the roast pot and stir to evenly coat.
Remove roast from oven and let cool 10 min before opening the parcel. Cut into smallish, bite sized chunks and lightly stir to combine. (We don’t want the seitan getting too broken up.)
Put lid on dutch oven/put foil on pan and place in the oven for 20 minutes. (we are basically just cooking the potato and carrot through here while infusing the seitan with the sauce.) Remove lid/foil and roast for 5 more minutes. Remove and let cool a few minutes before serving. Some seitan chunks will probably need to be shredded with two forks. Enjoy!