Chinese Barbecue Eggplant

Ingrédients

• 2 large Chinese or Japanese eggplants (about 14 ounces ; 400 g total)
• 5 tablespoons neutral oil , such as peanut, divided
• 8 medium cloves garlic , minced
• 2 fresh red Thai chiles , sliced
• 2 teaspoons oyster sauce
• 2 teaspoons granulated sugar
• 2 tablespoons light soy sauce , such as Lee Kum Kee
• 1 teaspoon MSG (optional)
• 2 scallions , white and green parts, thinly sliced cross-wise