Preheat the oven to 400°F then lightly grease a baking sheet (or line with parchment paper).
In a large bowl, whisk together the high heat oil, balsamic, tamari, smoked paprika, oregano and a pinch of salt & pepper. Add the sliced portobellos (with stems removed) to the bowl and toss until evenly coated. Set aside to marinate for 10 minutes.
Arrange the chopped asparagus, bell peppers, potatoes and onion on the baking sheet. Lightly spray with oil and sprinkle with salt & pepper. Add the mushrooms to the baking sheet and bake everything in the oven for 20-25 minutes, or until potatoes are tender.
Meanwhile prepare the pesto by combining all of the ingredients in a food processor or blender. Blend until smooth. Add water as needed to thin.
Arrange the cooked farro in separate bowls then top with roasted mushrooms and vegetables. Serve warm with pistachio pesto and enjoy!