Finely chop the carrot, celery and onion. Heat 1-2 tablespoons of olive oil in a large pot and saute the vegetables until soft but not browned (about 10-15 minutes).
Next, add the pancetta with the bay leaf and rosemary and cook for a further 5 minutes. Add the finely chopped garlic cloves and saute for another 3-4 minutes.
Add the white wine and let it reduce for a couple of minutes, then add the passata and vegetable stock. Add the lentils and stir in. Bring to a simmer, then cover and simmer on low for 30 minutes.
After 30 minutes, remove the lid and add a good pinch of black pepper. Add 400ml (1 and 3/4 cups) of water and the dried pasta. Bring back to a simmer and cook uncovered, stirring every so often until the pasta is al dente (about 10 minutes). Taste for seasoning and add salt if needed then serve.
Notes
Control the consistency - the pasta will start to absorb the liquid as it cooks. It the sauce gets too thick you can loosen it with more water.
Reheating leftovers - leftovers will keep well for up to 1 day (any longer and the pasta is too soft). Reheat on the stove until piping hot, add more water to adjust the consistency.
Freezing - I recommend freezing this before adding any pasta or additional water. Defrost completely then add the pasta and water whilst reheating on the stove.