Preheat the oven. Preheat the oven to 200°C/180°C Fan/Gas 6 and prepare a 1.8-litre (3¼ pint) oblong, shallow ovenproof dish.
For the cannelloni filling. Heat oil in a pan over high heat. Sauté the onion, then add garlic and minced beef, browning it while breaking it up with wooden spoons. Sprinkle flour, stir, and add stock, Worcestershire sauce, tomato purée, and thyme. Simmer covered for 30 minutes. Let it cool.
For the tomato and basil sauce. Heat oil in a saucepan, fry onions, add garlic, pour in tomatoes, tomato purée, water, salt, and pepper. Simmer covered for 30 minutes. Add sugar if needed, adjust seasoning, and stir in basil. Spoon one-third into the dish.
Assemble the beef cannelloni. Fill cannelloni tubes with the cold mince filling using a teaspoon. Arrange in a single layer in the dish and spoon the remaining sauce on top. Scatter mozzarella and Parmesan over and bake for 35–40 minutes until pasta is soft, and cheese is browned.
Serve. Serve hot with a green salad.
Notes
Mary’s Tips: Can be assembled up to 8 hours ahead. Freezes well before final cooking.