Preheat the oven to 200C/190C fan/gas mark 6 and put a metal baking sheet into it.
Brush a little olive oil around the inside of a large gratin dish . Slice the tomatoes about ½cm thick. Add a layer of tomatoes to the gratin dish – it can be higgledy-piggledy – then season. Add half the herbs, garlic, olives and goat’s cheese. Sprinkle on half the breadcrumbs. Drizzle with olive oil.
Repeat this, using up the rest of the ingredients, and drizzle with more oil. With this layer, overlap the tomatoes, so that they’re arranged neatly. The breadcrumbs won’t cover the top, but it’s good to see the tomatoes. Sprinkle the tomatoes with a little sugar.
Bake for 35 minutes, or until the gratin is bubbling and the tomatoes are a little caramelised in places.