Preheat the oven to 200C/400F/Gas 6.
Cut the tomatoes in half and place them, cut-side up, in a roasting tin or baking dish.
Peel the garlic, slice each clove in half and place one on top of each halved tomato.
Put the sprigs of thyme on top of the tomatoes, add coarsely ground black pepper, then trickle over the olive oil.
Roast for 25 minutes, or until the tomatoes are thoroughly soft.
Meanwhile, put the basil and oregano leaves in a food processor with the capers and the juice of the lemon.
Start to blend, pouring in the olive oil as you go.
Stop when you have a bright green dressing of pourable consistency.
To serve, take the tomatoes from the oven, transfer to a serving dish and pour the dressing around them.
