Preheat oven to 180 C / Gas 4. Pierce aubergines several times with a fork and place on a baking tray.
Bake in the preheated oven for 1 1/2 hours or until completely softened. Cool completely. Remove skin and finely chop. Transfer to a large mixing bowl and set aside.
In a frying pan, cook garlic in 1 tablespoon of oil over medium heat until lightly browned. Transfer to a small bowl. Stir in the remaining 2 tablespoons oil, the vinegar, sugar, oregano and basil until well blended and sugar is dissolved. Pour over the aubergine and toss to coat. Season to taste with salt and pepper and toss again. Cover and refrigerate for at least one hour before serving.