Heat a grill pan over medium-high heat or preheat a gas or charcoal grill. Grill the corn, turning every 5 to 6 minutes, until tender, about 15 minutes. When cool to handle, remove the kernels.

Rinse prawns under cold water and pat dry. Cut corn kernels off cobs and discard cobs. Set a large cast-iron skillet over medium heat and swirl in ⅓ cup olive oil. Add onions, garlic and red ...