To make the roasted vegetables, preheat the oven to 375 degrees Fahrenheit.
Toss the vegetables in ghee so they are covered all over. Add a good pinch of salt if your za'atar does not already include it. Then lay the vegetables in a single layer on a sheet pan (or two, if needed). Roast for about 20 minutes, then flip them over with a spatula. Continue roasting until they are browned.
Tip: They roast best when they are not touching and slightly apart. Make sure the brussel sprouts are cut side down.
Right as they come out of the oven, sprinkle them all over with za'atar spice.
Tip: We like to add the za'atar after roasting to prevent the sesame seeds in the za'atar from burning.
To make the tahini sauce, use a form or whisk to mix the lemon juice and tahini together. Add water 1 tbsp at a time while mixing, until the tahini has a consistency of coconut milk or cream. Whisk in the olive oil and season to taste, if desired.
Drizzle the olive oil & tahini over the vegetables and enjoy!