No soaking, husking, or de-silking required. If camping, make the spice mixture at home before you go.
- 1 teaspoon coriander seeds
- 2 teaspoons Aleppo pepper or ½ crushed red pepper flakes
- 1 teaspoon black sesame seeds
- 1 teaspoon toasted white sesame seeds
- 2 tablespoons unsalted butter, room temperature
Toast coriander seeds in a small dry skillet over medium heat, tossing often, until fragrant, about 1 minute. Let cool, then finely crush with the back of a knife. Combine coriander, Aleppo pepper, black sesame seeds, white sesame seeds, and salt in an airtight container.
Do Ahead: Spice mixture can be made 1 week ahead. Store at room temperature.
Build a charcoal or wood fire in a pit or a grill and allow fire to burn down until coals are completely covered with ash. Rake a layer of coals away from fire and place corn and leeks directly on top of embers. Roast, turning often and adding more hot coals as needed, until husks are charred and peel back easily from cob and leek greens are completely blackened and leeks are starting to collapse, 15–20 minutes. Let cool slightly. Shuck corn. Trim roots from leeks and halve lengthwise. Remove tender inner flesh; discard charred layers.
Spread corn and leeks with butter and sprinkle with some spice mixture. Dip lime quarters in remaining spice mixture and serve alongside corn and leeks.