Preheat the oven to 200C/180C fan. Cook the pasta in boiling salted water for 8 minutes, then drain - it will finish cooking in the oven.
Heat the olive oil in a large frying pan. Fry the bacon for 4 minutes until starting to crisp, then add the onion and cook for another 5 minutes until soft.
Add the garlic and oregano, stir for 1 minute, then pour in the chopped tomatoes and drained lentils. Simmer for 5 minutes.
Mix the cooked pasta into the sauce, then transfer everything to a baking dish.
Mix the breadcrumbs with the grated cheese and dried herbs, then scatter evenly over the top.
Bake for 20 minutes until the topping is golden and crispy. Serve straight from the dish.