Heat 2 tbsp oil in an oven-proof frying pan over a medium heat. Add the aubergine and onion and fry for five minutes to soften. Add the garlic and transfer to the oven and cook for ten minutes. Meanwhile, heat a griddle pan or grill. Brush the ciabatta with oil and grill the bread on each side for 1-2 minutes, or until brown stripes appear. Remove the aubergine from the oven and place into a food processor with the basil and a 1 tsp of oil. Blend to a rough paste and pour out into a bowl. Serve the aubergine mixture with the griddled bread.