Preheat the oven to 450°F. Smash the garlic cloves with the side of the knife.
Place the cauliflower florets and smashed garlic on a large rimmed baking sheet and drizzle with olive oil.
Season with cumin, salt, and crushed red pepper flakes. Sprinkle evenly over cauliflower, tossing well to coat evenly.
Bake in the center of the oven until browned and tender, about 25-30 minutes, turning the florets occasionally so they are evenly cooked. Remove from the oven, squeeze with lime juice and top with lime zest and cilantro; serve warm.