Cut the carbonade into 4 equal pieces and beat them to a thickness of 1 cm. RUB with salt, pepper and Provencal herbs, drizzle with olive oil, place on a parchment-lined baking sheet and leave to marinate while everything else is cooked.
Preheat the oven to 170 °C. Thinly slice the tomato.
Peel the onion and cut it into 1.5 cm thick circles. Trying to keep the mugs intact, put them in a slightly heated frying pan with oil. Add salt and fry over high heat for 2 minutes. on each side.
Peel the onion and cut it into 1.5 cm thick circles. Trying to keep the mugs intact, put them in a slightly heated frying pan with oil. Add salt and fry over high heat for 2 minutes. on each side.
Carefully, using a wide spatula, transfer the onion to the meat pieces. Put the tomatoes on the onion, drizzle with olive oil, salt and place in the top third of the oven for 15 minutes.
Place the cheese slices on the meat on top of the tomatoes and return the pan to the oven so that the cheese melts and Browns slightly. Serve the pork very hot.