Preheat the oven to 375°. Brush the eggplant slices on both sides with the olive oil and arrange on a lightly oiled rimmed baking sheet. Bake for about 30 minutes, or until very soft and lightly browned. Let the eggplant cool slightly, then transfer the slices to a cutting board and chop coarsely. In a medium bowl, combine the eggplant with the yogurt and garlic and season with salt. Serve at room temperature.