1. Adjust the oven rack to the lower third of the oven. Preheat the oven to 400 degrees Fahrenheit and line a baking sheet pan with parchment paper.
2. Remove the outer leaves of each cauliflower head and cut the bottom stem off so the cauliflower can sit flat on your cutting board. Keep the core intact.
3. Place the cauliflower stem-side down on the cutting board and with a large sharp knife, cut the cauliflower in half lengthwise through the center.
4. Cut two 1-inch steaks from each half. You can reserve the smaller florets for another use or you can roast them in a separate sheet pan. Repeat the process with the other cauliflower head. The total number of steaks you get will depend on the size of the cauliflower. Usually you can get 8 steaks from 2 large cauliflowers.
5. Combine the salt, pepper, garlic powder and paprika in a small mixing bowl.
6. Place the cauliflower steaks on a single layer on the baking sheet pan, drizzle or brush one side with oil and season with the spice mix. Flip the cauliflower steaks and repeat, drizzling the oil and seasoning with the spice mix.
7. Bake for 15 minutes, then gently flip the cauliflower steaks and bake for another 15 to 20 minutes or until tender and deeply golden brown.
8. Transfer to a serving platter and garnish with chopped parsley. Serve with the tahini dressing.

Lemon Tahini Dressing

1. Whisk all the ingredients together until smooth. Reserve until ready to use.