For the pesto, place all the pesto ingredients, except the Cabernet Sauvignon vinegar, into a food processor and blend to a fine purée. Set aside.
For the croquettes, preheat the oven to 160C/320F/Gas 2.
Preheat the oil in a deep fat fryer to 160C. (CAUTION: Hot oil can be dangerous. Do not leave unattended.)
Place the potatoes into a saucepan of salted water and bring to the boil. Cook for 12-18 minutes, or until tender, then drain and return to the pan.
Place the pan of potatoes back over the heat until all the moisture has evaporated. Mash with a potato masher or ricer until smooth.
Add the parmesan cheese, one tablespoon of the red pesto, and all the sun-blushed tomatoes and basil to the mash and mix well. Add salt and freshly ground black pepper, to taste. (Add a little flour if the mixture is too wet to form into shapes with your hands.)
Divide the mixture into 12 equal-sized pieces and shape into cylinder croquettes, using your hands. Push a small piece of mozzarella into the centre of each croquette, closing up the potato to completely cover the mozzarella.
Place the remaining flour and the breadcrumbs onto two separate plates. Place the eggs in a bowl. Dredge the croquettes in the flour, then dip them into the beaten eggs and finally roll them in the breadcrumbs, to cover, retaining the shape.
Carefully lower a few croquettes at a time into the preheated deep fat fryer and cook for 3-4 minutes, or until golden-brown and crisp. Remove with a slotted spoon and drain on kitchen paper. Transfer the croquettes to a roasting tray and place in the preheated oven to keep warm.
To serve, add the Cabernet Sauvignon vinegar to the remaining pesto and place a spoonful onto each of four plates. Place three croquettes on top of each dollop of pesto and garnish with rocket.