Preheat oven to 400°F.
Begin by removing the greens from the beets by cutting them off at the base. Trim and discard the tough stems. Chop the greens and set aside.
Meanwhile peel the beets and the sweet potatoes and cut them into bite size cubes. Place the sweet potatoes in a bowl and toss with 3 tbsp of the oil. Spread the sweet potatoes on one side of a baking sheet. Do the same with the beets and spread them on the baking sheet next to the sweet potatoes. Sprinkle the ground cumin over the beets and sweet potatoes and salt to taste/preference.
Place the baking sheet in the preheated oven and cook for about 45 minutes or until the beets are tenter when poked with a fork (the sweet potatoes will cook a little faster, but it's okay if they get a little soft - they will be sweeter and more flavorful too.)
About 20 minutes before the potatoes and beets are done cooking, begin preparing the quinoa (enough for four servings) per package directions.
While the quinoa cooks, sauté the beet greens in the remaining 1 tbsp of oil, just until slightly wilted (about 2 minutes). Set aside. Slice up the avocado and set aside.
For the garnish, take a small handful of cashews and toss them into a small, dry skillet. Turn the burner to medium heat and toss the nuts around until they begin to toast (you will smell them). Watch this step as the nuts can easily burn if unattended. Remove the skillet from the heat when finished and pour the nuts into a bowl.