Roast the eggplants: Preheat oven to 200°C. Slice the eggplants in half lengthwise. Score the cut side of the eggplants in a crosshatch pattern with a sharp knife, in lines about an inch apart. Poke the skin sides of the eggplants with the tines of a fork all over.
Line a pan with foil. Spread olive oil over the bottom of the pan, and sprinkle evenly with salt. Place the eggplants cut side down on the foil lined pan. Place in the oven and cook for 35 mins, or until completely cooked through and very soft.
Once the eggplants have cooled to the touch, peel off the tough outer skin and discard.
Place garlic, peeled eggplant, cherry tomatoes, caciocavallo and basil in a food processor and pulse until smooth.
Place the eggplant mixture in a piping bag, for an easier handling.
Fill each bocconcini leaf cannelloni style, serve cold or hot.