01 - Preheat oven to 425°F. Line a baking sheet with parchment paper or foil.
02 - Remove any tough outer leaves from the cabbage. Slice from top to stem into 1-inch thick steaks (you should get about 4–6 slices).
03 - Arrange cabbage steaks in a single layer on the prepared baking sheet. Brush both sides with olive oil and season with salt and pepper.
04 - Roast for 25–30 minutes, flipping once halfway, until the edges are browned and the centers are tender.
05 - While cabbage roasts, whisk together tahini, lemon juice, minced garlic, salt, olive oil, and cumin (if using). Add warm water, a little at a time, until the sauce is smooth and pourable.
06 - Transfer cabbage steaks to a serving platter. Drizzle generously with lemon tahini sauce. Garnish with chopped parsley, toasted sesame seeds, and red pepper flakes if desired. Serve warm.