Position an oven rack 4–5 inches (10-12 cm) from the heat source and preheat the broiler until very hot.
Gently break off and discard the mushroom stems. Wipe the caps clean with a damp paper towel and let them air dry for a few minutes.
Place the mushroom caps, gill side up, on a baking sheet.
Brush them with 1 tablespoon (15 ml / 0.5 fl oz) of oil.
Broil for about 1½ minutes, or until the gills are well singed and fragrant. Carefully flip the caps over.
Brush the smooth side of the caps with the remaining 1 tablespoon (15 ml / 0.5 fl oz) of oil and broil for another 1½ minutes until they have a beautiful char.
Transfer the hot mushrooms to a serving plate, placing them gill side up. Immediately sprinkle with half the salt, half the lime juice, and half the chili paste or powder. Gently spread the seasonings over the gills with your fingers or a small brush.
Turn the mushrooms over and season the other side with the remaining salt, lime juice, and chili.
Serve immediately.