Heat the oven to 400F.
In a mixing bowl, combine shiitake mushrooms with salt, garlic powder and onion powder.
Prep the sauce by zesting and juicing a lime in another bowl, then mixing them with the rest of the sauce ingredients.
Peel and chop the butternut squash into small cubes. Mix with olive oil and salt on a baking sheet and spread out evenly, being mindful not to overcrowd.
Rinse and chop the broccoli into small florets. Mix with olive oil and salt on a separate baking sheet and spread out evenly, being mindful not to overcrowd.
Bake broccoli and butternut squash in the oven for 20 minutes, or until they can easily be pierced with a fork.
While the broccoli and squash are baking, rinse and chop the cauliflower into small florets. Using a food processor, shred the cauliflower into rice.
Heat 2 tablespoon olive oil in a large saute pan on medium-high. Add cauliflower and ¼ teaspoon salt. Cook for 3 minutes, stirring occasionally. Transfer cauliflower to a bowl and cover to keep warm.
Using the same saute pan as the cauliflower, add another 2 tablespoon olive oil on medium-high. Spread mushrooms evenly throughout the pan. Set a timer and cook mushrooms for 3 minutes, undisturbed. Stir. Repeat timer for another 3 minutes and cook mushrooms, undisturbed. Stir.
Add the sauce to the pan with the mushrooms and cook for 2 minutes, stirring occasionally.
Add roasted broccoli and squash to the pan and cook for a final 2 minutes, stirring frequently to combine everything.
Serve over warmed cauliflower rice and enjoy!