Step 1

Preheat oven to 425°F. Cut cauliflower into medium pieces, toss on a large rimmed baking sheet with the sliced onion, thyme, 4 unpeeled garlic cloves, and olive oil. Season with salt and pepper. Roast, tossing occasionally, until just starting to char, 35-40 minutes.

Step 2

Sprinkle the cauliflower with the juice of 1 lemon, toss to combine, and roast until cauliflower is tender, 10-15 minutes longer.

Step 3

In a small bowl, whisk together the tahini, lemon, oil and garlic. Whisk until smooth. Add the water and continue mixing until pourable and season with salt.

Step 4

Drizzle the tahini sauce over the cauliflower and serve with extra lemon as needed.