In a medium bowl, mix olive oil, balsamic vinegar, lemon juice, fresh rosemary, garlic, salt, and pepper. Add the steak to the marinade and let it sit while you prepare the other ingredients.
Let’s make the quinoa! Add 2 cups of quinoa in 3 1/2 cups of water or broth in a medium pot on the stove. Bring to a boil over medium heat. Once it starts boiling, put the heat to low, cover and let it simmer for about 15 minutes.
Chop the red bell pepper, mushroom, brussel sprouts, and red onion, add them to a bowl, then toss in olive oil and a sprinkle of salt. Spread the veggies evenly on an oiled sheet pan and bake at 425°F for 15-20 minutes.
Cook the steak to how you prefer it. To achieve a medium-rare steak, preheat a cast iron over high heat, add the steak and cook it in the cast-iron skillet for about 3-4 minutes per side or until the internal temperature has reached 125°F. Let the steak rest for 5 minutes once it’s been removed from the heat. The internal temperature should then be 130°F-135°F. Cut the steak into bite sized pieces for the bowls. I like 1/2 inch cubes.
Assemble the steak and roasted veggie grain bowls by placing quinoa at the base, adding the steak, roasted veggies, balsamic glaze, a sprinkle of feta cheese, and a squeeze of fresh lemon. ENJOY!