Gather the ingredients.
Cut off any stems and impurities on the skin of the aubergines. Cut the aubergines crossways into slices about 3/4 inch thick.
Place a wire rack in the center of the oven and turn the grill on high. Place the eggplant slices on a foil-lined rimmed baking sheet. Brush each slice lightly with olive oil. Place the baking sheet on the middle shelf so it is not too close to the heating element or the eggplant will burn.
When one side of the eggplant is lightly browned and soft when pressed, flip the slices, brush with more olive oil, and return to the grill.
Depending on your grill, it may take 15 to 25 minutes to cook. (You may find that the slices that are directly under the grill cook much faster than the slices at the back corners of the pan. Keep an eye on the pans and rotate the slices on the baking sheet if necessary.)
Take out the finished slices one at a time and place them on a large platter or serving dish. Don't be afraid to overlap the slices on the serving plate. It is great for serving and looks more appetizing.
While the eggplant is cooking, finely chop the tomatoes and place in a medium bowl. Finely chop the spring onions and add to the bowl. Press the garlic cloves through a press or crush them by hand and add to the bowl.
Remove the capers from the jar with a slotted spoon to allow them to drain. Chop the capers and add to the bowl. Be sure to remove the stems from the basil leaves, then chop the basil and add to the bowl.
Add vinegar and olive oil to bowl, if desired, and mix well. Adjust the seasonings with salt and pepper.
Let the eggplant cool for a few minutes. Then spoon the tomato vinaigrette sauce over the eggplant. Garnish with basil leaves.