Heat the olive oil in a heavy-based pan and fry the eggplant on both sides until lightly golden. Remove from the pan and drain on kitchen paper.
Arrange the tomatoes on kitchen paper for an hour or so to drain away as much moisture as possible.
Line a terrine mould up the sides with the eggplant. Next, fill the mould with layers of tomato and basil leaves, salting each layer lightly as you go.
When you reach the top of the mould, dissolve the gelatine in the warm stock and pour over the tomatoes. Cover with more slices of eggplant.
Weight the terrine and refrigerate for a few hours. Cut into slices to serve.