Bring a large pot of water to boil. Add the rice and simmer until the rice is mostly tender. 30-45 minutes. (Prep ingredients and start on #2 while rice is simmering). Drain and add back to the rinsed large pot.
Place cauliflower, sundried tomatoes, mushrooms and carrots into a medium saucepan and cover with water. Bring to a boil. Lower heat and allow to cook at a low boil until tender, about 15 to 20 minutes. Remove from heat and drain into a colander.
Transfer cauliflower medley to a food processor. Add 1 cup of plant milk, the nutritional yeast and miso and blend until completely smooth, stopping to scrape down sides of bowl as needed.
Add broccoli, onion and garlic to the pot with the rice. Add in the cauliflower sauce. Stir and bring to a low simmer. Cook just until broccoli is tender and bright green, about 3 minutes. If needed, thin with more milk. Season with salt and pepper. Serve.