Ratatouille lasagne

Name: Ratatouille lasagne
Ingredients: 600ml milk, plus a little extra; 1 x 30g pack basil, stalks separated and leaves shredded; 50g butter; 50g plain flour; ½ tsp grated nutmeg; 100g vegetarian hard cheese (or Parmesan), grated; 10-12 dried lasagne sheets; 3 large vine tomatoes, sliced into thin rounds; 1 x 125g mozzarella ball, sliced thinly; 15g pine nuts, toasted and chopped; 2 large red onions; 3 mixed peppers, deseeded; 2 aubergines; 2 courgettes; 3 tbsp olive oil; 4 garlic cloves, crushed; 1 tbsp dried oregano; 1 tbsp tomato purée; 2 x 400g tins chopped tomatoes; 1 tbsp balsamic vinegar; ½ tbsp brown sugar