Combine oil and garlic; brush over both sides of eggplant slices.
Place on a greased baking sheet.
Bake at 425° for 15 minutes; turn.
Bake until golden brown, about 5 minutes longer. Cool on a wire rack. Reduce oven setting to 350°.
Place half the eggplant in a greased 1-qt. baking dish.
Sprinkle with half the basil and half the Parmesan cheese. Arrange tomato slices over top; sprinkle with remaining basil and Parmesan.
Layer with half the mozzarella cheese and the remaining eggplant; top with remaining mozzarella. Cover and bake for 20 minutes. Uncover; bake until cheese is melted, 5-7 minutes longer.