Mince garlic and mash to a paste with a pinch of salt, then transfer to a bowl.
Prepare grill for cooking.
Brush eggplant slices generously with oil on both sides and sprinkle with remaining 3/4 teaspoon salt.
If you're using whole-milk plain yogurt instead of lebneh, you'll have to
Ingredients
1/2 cup lebneh* (thick Middle Eastern�style yogurt)
allow extra time (at least 8 hours) for draining.
or 1 cup whole-milk plain yogurt
1 garlic clove
1 teaspoon salt
2 to 4 tablespoons water
2 lb eggplant (2 medium), cut crosswise into 3/4-inch-thick slices
1/2 cup olive oil
covered and chilled, 8 to 12 hours.
Whisk in lebneh or drained yogurt, 1/4 teaspoon salt, and enough water
to make mixture resemble well-stirred sour cream.
If using a charcoal grill, open vents on bottom of grill, then light charcoal.
Charcoal fire is medium-hot when you can hold your hand 5 inches above rack for 3 to 4 seconds.
If using a gas grill, preheat burners on moderately high, covered, 10 minutes,
then reduce heat to moderate.
Grill slices on lightly oiled grill rack, covered only if using a gas grill,
turning over occasionally, until eggplant is tender, 12 to 15 minutes total.
Transfer as cooked to a platter, arranging slices in 1 layer.
Put a spoonful of yogurt mixture on each eggplant slice and top with a mint leaf.