1.	Preheat the oven to 180C/gas 4. Line a baking tray with baking parchment.
2.	Cut the tomatoes in half lengthways and place on the tray, cut side up. Drizzle with the olive oil, season lightly and bake for about 1½ hours, until they colour and shrink a little (if after an hour they start to colour too much - cover with foil).
3.	About 30 minutes before the tomatoes are due to be ready; season the chicken breasts and steam over a high heat for about 12-18 minutes, depending on the thickness of the breasts. Remove from the steamer, cover with cling film or foil and leave to cool to room temperature.
4.	Thinly shave the fennel and place in iced water to crisp up.
5.	Mix the beans with the sliced onion, bean sprouts, parsley and lemon juice and season lightly.
6.	For the dressing, mix together the soy sauce, olive oil, truffle oil and lemon juice. Taste and adjust the seasoning as necessary.
7.	Divide the bean salad between 4 plates and sit the tomato halves on top. Slice each chicken breast into 4 pieces and arrange over the bean salad. Toss the fennel with the dressing, scatter over the chicken and serve.