Prep. Preheat your oven to 425°F and line a baking sheet with parchment paper.
Slice the cauliflower. Remove the leaves from the cauliflower heads and trim the stem end to create a flat base for the cauliflower to stand on. Slice each cauliflower head vertically into 1-inch thick slices, creating "cauliflower steaks." Don’t worry if the ends fall apart a bit. You can still roast those.
Season the cauliflower. Whisk together the olive oil, lemon juice, salt, pepper, garlic powder, and half of the parsley. Brush both sides of each cauliflower steak with the olive oil mixture.
Roast. Arrange the seasoned cauliflower steaks in a single layer on the prepared baking sheet. Roast for 25 to 30 minutes or until the cauliflower is tender and golden brown, flipping them halfway through cooking.
Serve. Serve them warm, drizzled with olive oil, and garnished with the remaining parsley.
Notes
Parchment Paper is Key: Stick to parchment paper for baking. It prevents sticking much better than aluminum foil, which cauliflower tends to cling to.
Selecting Cauliflower: Choose large, tightly packed cauliflower heads. Loosely packed ones may crumble when cut into steaks.
Consistent Thickness: Cut the cauliflower steaks about 1 inch thick. Uneven sizes mean uneven cooking.
Sharp Knife: Use a large, sharp chef's knife for cleaner cuts.
Gentle Handling: Carefully transfer the steaks to the baking sheet or pan to avoid breaking.
Use Leftovers: Don't waste the smaller pieces that break off. They can be roasted alongside the steaks.
For a Smoky Twist: Skip the lemon and parsley. Instead, mix in smoked paprika and cumin. For a different flavor, finish with a dash of lime and chopped cilantro.
Cheesy Topping: Try adding freshly grated parmesan about 10 minutes before the end of baking. It'll melt and get slightly crispy.