Bring the vegetable broth to a simmer in a small pot over medium-high heat. Add the quinoa and millet and reduce the heat to a simmer. Simmer for 15 minutes or until the quinoa and millet are cooked and the liquid is absorbed. Remove from heat and fluff with a fork.
In a medium skillet over medium heat, heat the olive oil. Add the onions and sauté until tender, about 10 minutes. Add the black beans, garlic, cumin, and grapes, cooking for a few minutes until fragrant. Remove from heat.
Transfer the grains to a large mixing bowl, and add onion-bean mixture and toss to combine. Stir in remaining ingredients, season with salt and pepper to taste, and toss with nutritional yeast.
Garnish with additional cilantro.
Slightly modified from Natural Noshing blog.Calories were calculated using the VeryWell Fit nutrition calculator for 4 servings.