Grilled Cauliflower Steaks and Scallions

Ingredients

  • 1 large head cauliflower
  • 6 tablespoons vegetable oil, divided, plus more for grill
  • 1 bunch scallions, trimmed
  • Kosher salt, freshly ground pepper
  • 1 1-inch piece ginger, peeled, grated
  • 1 garlic clove
  • ½ cup (packed) fresh cilantro leaves
  • 2 tablespoons fresh lime juice
  • Gochugaru (Korean red pepper powder), toasted black sesame seeds, and sesame oil (for serving)