Add the herbs, tomatoes and stock, and simmer, uncovered, for 15-20 mins until the tomatoes have broken down – it should still be quite thin. Add the lasagne pieces, one by one, and stir well, so they don’t stick together. Simmer for 5-8 mins until the pasta is al dente. Top up with a little water if it starts to get too thick. Taste for seasoning.
