Preheat the oven to 200C/180C Fan/Gas mark 6.
Mix the ricotta, grated parmesan, lemon juice and zest and dried oregano together in a bowl.
Brush the sliced aubergine rounds with a little olive oil on each side. Fry the aubergine slices in a griddle or non-stick pan over a medium heat for a few minutes each side. This will help them to cook in the oven rather than steam.
For the tomato sauce, add 3 tbsp olive oil to a pan over a medium heat. When the oil starts to shimmer, add the sliced onions and salt and cook for about 5-10 minutes. Stir regularly to make sure the onions colour evenly and don’t burn. Add the chopped garlic to the pan and cook for a further 2-3 minutes. Add the fresh or tinned chopped tomatoes and tomato puree and cook for another 10-15 minutes, stirring regularly. You want the tomatoes to reduce and become thick and saucy. Remove from the heat and blend with a stick blender. Add 50 ml olive oil, the ‘nduja (if using) and season with more salt (if needed) and lots of freshly ground black pepper. Stir until everything is combined.
Add a layer of tomato sauce to an ovenproof dish, followed by a layer of aubergine. Repeat with the remaining sauce and aubergine. Top with the ricotta mixture and finish with the slices of mozzarella and a drizzle of olive oil. Bake in the oven for 25-30 minutes or until the aubergines are soft and cheese has melted.
To make the pangritata, add everything but the pine nuts and olive oil to a food processor and blitz to make breadcrumbs. Add a large glug of olive oil to a frying pan over a medium heat. Add the breadcrumb mixture and pine nuts to the pan and cook until golden and toasted, stirring regularly to avoid them burning. Remove from the heat and set aside.
Remove the aubgerine dish from the oven and allow to stand for a few minutes. Finish with the pangritata and fresh basil leaves.