Make marinade by whisking together all of the ingredients in a large bowl or container. Place tempeh cubes into the bowl and place in the fridge to marinade for at least 2 hours, preferably overnight.
Roast brussels sprouts: Preheat oven to 400°F. Wash, trim and chop brussels sprouts before adding them to a roasting pan with olive oil, sea salt and pepper. Toss to combine and roast for 35-40 minutes, or until cooked through with some golden brown spots. Be sure to toss around the 20-minute mark.
While brussels sprouts are roasting, cook quinoa by adding 1 cup dry quinoa to 2 cups of water or broth in a saucepan. Bring liquid to a boil, reduce heat to a simmer, cover and cook for 15 minutes, or until no liquid remains. Remove from heat and use a fork to fluff the quinoa.
Cook tempeh by adding 1-2 teaspoons of oil to a pan over medium heat. Use a slotted spoon to remove tempeh from the marinade and place in the pan. Cook tempeh cubes until all sides are golden brown, about 6-8 minutes. Remove from heat.
At this point, you can serve the dish as is or let everything cool before dividing everything into four meal prep containers. For the containers, each gets 3/4 cup of cooked quinoa, about 1 1/2 cups roasted brussels sprouts, 5 cubes of tempeh and 3/4 cup mixed greens. Place leftover marinade in a storage container and save to use as a dressing for the bowls when ready to serve.