Heat grill pan or grill to medium-high. Grill eggplants, turning often until very soft, about 15 minutes.
While eggplants grill, cook sliced garlic in olive oil in a small skillet over medium heat, 2-3 minutes. Remove from heat and add red pepper flakes and salt. Set aside.
Remove eggplants from grill and trim ends off and split down the middle. Scrape the flesh with a fork, then drizzle with garlic oil and fresh mint.