1. Heat your oven to 190C/Gas Mark 5.
2. Top and tail the aubergines, the slice in rounds that are 1cm thick. Season and brush each side using half the olive oil, then place on a non-stick baking tray and cook for 30 minutes until soft and golden. Leave to one side.
3. While you are waiting for the aubergines, make your tomato sauce by heating the remaining oil in a frying pan, then cooking the garlic for a few seconds before pouring in the tomatoes. Bring to the boil then add the thyme, sugar and seasoning. Keep on a high simmer for approximately 15-20 minutes, so the sauce thickens. When ready, remove the sprigs of thyme and add further seasoning if required.
4. Brush 4 ramekins with oil, then cover the base of each with a cooked aubergine slice. Top with a spoonful of ricotta followed by a spoonful of tomato sauce and then another aubergine slice. Repeat until you have a full ramekin topped with aubergine.
5. Bake in the oven for 20 minutes. Once they have cooled slightly, carefully turn upside down until the timbale comes loose and serve.