Preheat your oven to 425°F (220°C). Line a large baking sheet with parchment paper.
Remove the leaves from each cauliflower head and trim the stem flat so it can stand upright on your cutting board.
Starting from the center, cut each cauliflower into 1-inch thick slices. You'll typically get 2-3 good "steaks" from each head, with some florets falling away (save these for roasting too!).
In a small bowl, mix olive oil, minced garlic, paprika, cumin, salt, and pepper.
Brush both sides of each cauliflower steak with the seasoned oil mixture, making sure to get into all the nooks and crannies.
Place the steaks on your prepared baking sheet, giving them plenty of space.
Roast for 25-30 minutes, carefully flipping halfway through, until golden brown and tender when pierced with a fork.