Slice open pumpkin, scoop out seeds and set aside. Season the inside of the pumpkin with olive oil, salt and pepper and roast in oven for 40 minutes. Remove from oven and when cool enough to handle dice into bite size pieces. I kept the skin on (I actually love the texture of the skin) alternatively you can remove the skin. You will need about 2 cups of diced pumpkin for the tacos.
In the meantime prepare shiitake mushrooms by removing stems. Drizzle 1 tbsp olive oil on a large sheet tray and arrange mushrooms in a single layer. Sprinkle with 1/4 tsp sea salt and 1/4 tsp black pepper. Roast for 10 minutes (in 350° oven, I roast them while the pumpkin is roasting), remove from oven, flip mushrooms and roast for additional 10 minutes.
While pumpkin and mushrooms are roasting prepare onion pepper mixture. In a large skillet over medium high heat saute onion and pepper in olive oil for 5 minutes or until tender. Add a little bit of water if more liquid is needed. Add chili powder, salt and pepper stir well to combine
Combine vegenaise, lime juice, salt and pepper in a medium bowl. Whisk well to combine. Toss with cabbage, set aside.
Spiced pumpkin seeds
Wash seeds and spread out in a single layer on a cookie sheet lined with a kitchen towel. Dry thoroughly (alternatively leave the seeds out in open air overnight to dry). When dry toss with melted coconut oil and spices. Roast in 350° oven for 10 minutes. Store in an airtight container for up to one week.
Toast corn tortillas over an open flame, lay tortillas flat and top with onion pepper mixture, pumpkin, and shiitake mushrooms. Top with a bit of slaw, sliced jalapeno, fresh cilantro, pumpkin seeds, and a squeeze of lime juice.