Tip the tomatoes into a pan with a can of water, the tomato purée, garlic, olives and bouillon. Add the aubergine and courgettes, then cover and simmer for 30 mins until the veg are tender.
Meanwhile, mix the ricotta and basil together in a small bowl with plenty of black pepper.
Boil half of the pasta following pack instructions, then drain, reserving some of the cooking water. Tip into a bowl and toss with half the ricotta mixture and a couple of spoonful of pasta water, adding more to loosen if needed. Spoon half the ratatouille and the penne into two pasta bowls and sprinkle with half the parmesan and basil leaves. Cover and chill the remaining ratatouille, basil and ricotta for another night. Will keep chilled for up to three days. When ready to serve again, warm the ratatouille in a pan over a low heat and continue with the method from step 3.
