Preheat the oven to 400°F. Line a rimmed baking sheet with parchment paper.
In a shallow baking dish or container, place balsamic vinegar, truffle salt, and black pepper. Stir to combine and place in sliced mushrooms. Toss gently to coat and allow to marinate for 10 minutes.
Place red bell peppers and red onions on lined baking sheet. Toss with 1-2 tbsp of balsamic vinegar and truffle salt and black pepper to taste.
Heat a large skillet over high heat. Place marinated mushrooms and liquid into pan and saute over medium-high heat. Cook for 2-3 minutes per side until mushrooms are browned.
Add sauteed mushrooms to peppers and onions. Bake for 15 minutes, gently toss, cook for addional 15 minutes until vegetables are roasted.
Keep oven at 400°F and line a rimmed baking sheet with parchment paper. Place sweet potato toasts on prepared baking sheet and bake for 10 minutes per side.
To assemble, place sweet potato toast on a plate and top with roasted vegetables, artichoke hummus, and vegan cheese of choice*.