Wash and cut all of your veggies before beginning this recipe. I've provided information on how each veggie should be cut in the ingredients list.
Preheat the oven to 400°F (200°C). Put the beets in a metal roasting pan that was covered with parchment paper. Drizzle the beets with ½ tablespoon of olive oil. Roast for 15 minutes in the top third of the oven.
While the beets bake, mix the onions, squash, carrots, and Brussels sprouts with 3 tablespoons of olive oil. (Note: If you are using Brussels sprouts leaves or other leafy greens, don’t mix them with oil yet! Instead, just mix the onions, squash, and carrots with 2 tablespoons of oil.)
Add the veggies in the previous step (EXCEPT Brussels sprouts tops) to the roasting pan with the beets. Try to get everything into a single layer. Roast an additional 30 minutes at 400°F (200°C).
While the veggies bake, clean the squash seeds and pat dry. Mist a dark baking sheet with cooking spray. Spread the seeds on the sheet in a single layer and mist them with more cooking spray.
When the time is up for the veggies, take them out of the oven to flip and stir. Mix the veggies with the dried thyme, rosemary, salt, and black pepper. Push the veggies in the pan aside to make room for the Brussels sprouts leaves (if using). Mix the leaves with 1½ tablespoons of oil and add them to the pan. Turn the oven down to 350°F (175°C).
Put the roasting pan with the veggies back in the top third of the oven. Place the baking sheet with the seeds on a lower oven rack.
After 15 minutes, take the squash seeds out of the oven, salt them, and set them aside. Take the veggies out of the oven, flip and stir them once more, and cook an additional 10 minutes.
Cook the quinoa in water according to the quinoa's package directions. This will take about 20 minutes. Set the quinoa aside.
Sprinkle salt and pepper on the chicken breasts. Cook the chicken breasts on a stovetop grill pan that has been misted with cooking spray. It takes about 8-10 minutes per side. (Pro tip: skip this step by using store-bought grilled chicken strips.) Grilled chicken should reach a minimum safe internal temperature of 165°F (74°C).
Cut the chicken into bite-sized slices. Set the chicken aside.
Now make the tahini sauce. Whisk the tahini, garlic, water, lemon juice, and zaatar seasoning together. The dressing will seem thin at first but it thickens as it sits.