Puttanesca lasagne

Ingredients

• 2 tbsp olive oil
• 2 aubergines, cut into 2cm chunks
• 1 red onion, chopped
• 3 garlic cloves, crushed
• 1 x 50g tin anchovy fillets, drained and chopped
• pinch of chilli flakes
• 2 x 400g tins chopped tomatoes
• 2 tbsp capers, rinsed and drained
• 100g pitted kalamata olives, halved
• 1 tbsp light brown soft sugar
• about 9 dried lasagne sheets
• 50g unsalted butter
• 50g plain flour
• 650ml whole milk
• 1 x 150g mozzarella ball, drained and chopped
• 100g parmesan, grated