Heat the oven to 200C, gas 6. Heat the oil in a large ovenproof pan. Add the frozen mash, stir until softened, then add the rest of the vegetables. Heat, stirring, until defrosted.

Dry-fry the bacon in a frying pan until crispy on both sides. Once the mash mix is heated through, arrange the mozzarella, pesto and pine nuts on top and place in the oven to melt. Top with the bacon, basil leaves and rocket, to serve.