Preheat your oven to 220°C/200°C fan/gas mark 7.
Trim the aubergine, then slice into rounds approximately 1cm thick. Pop them onto a large baking tray. Drizzle with oil, season with salt and pepper, then toss to coat. Spread out in a single layer.
When the oven is hot, roast on the top shelf until soft and golden, 20-25 mins. Turn halfway through.

Meanwhile, bring a large saucepan of water to the boil with 1/2 tsp salt.
Halve, peel and thinly slice the red onion. Peel and grate the garlic (or use a garlic press).
Drain the mozzarella and tear it into small pieces.

When your pan of water is boiling, add the penne and bring back to the boil. Cook until tender, 12 mins.
Once cooked, drain in a colander and pop back in the pan. Drizzle with oil and stir through to stop it sticking together.

Meanwhile, heat a drizzle of oil in a large frying pan on medium-high heat.
Once hot, add the onion and fry until softened, 5-6 mins.
Stir in the tomato puree and garlic and cook for 1 min more, then pour in the chopped tomatoes, veg stock paste, sugar and waterfor the sauce (see ingredients for both amounts). Season with salt and pepper, then bring to the boil.
Lower the heat to medium and simmer until the sauce has thickened, 6-8 mins.

Taste the sauce and add salt, pepper and a pinch of sugar if necessary. Stir through the cooked pasta and half the hard Italian style cheese.
Transfer half the pasta to an ovenproof dish. Layer the roasted aubergine slices over the top, then cover with the remaining pasta. Scatter evenly with the mozzarella pieces and remaining hard Italian style cheese.
Switch your oven to grill setting on high heat.
Once hot, grill the pasta until the cheese is golden and bubbling, 5-6 mins.

Cut the tomato into 1cm pieces, then add to a medium bowl with the balsamic vinegar and olive oil for the dressing (see ingredients for amount). Season with salt and pepper.
Just before serving, add the rocket to the tomatoes and toss to coat in the dressing.
Serve your aubergine parmigiana bake in large bowls with the rocket salad alongside. Enjoy!