Clean, wash and halve the tomatoes. Folded up, put them on a baking tray coated with oil. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for approx. 15 minutes.
In the meantime, drain the mozzarella, squeeze it carefully between kitchen paper. Cut each ball into 8 slices. Wash the basil, shake dry and pluck the leaves from the stalks. Put some leaves aside for garnishing.
For the vinaigrette, mix vinegar and honey. Season with salt and pepper. Fold in the oil. Remove the tomatoes from the oven, remove the tops carefully and season the tomatoes with salt and pepper. Spread 2 slices of mozzarella and 2 slices of basil leaves on each of the lower halves.
Place the upper tomato halves back on top and sprinkle evenly with vinaigrette.
Continue baking at the same temperature for about 5 minutes. Remove from the oven and garnish with some pesto and basil.