In a large lidded heatproof cooking pot add 1tbsp olive oil and then add the onions. Fry on a low heat for 5 minutes until soft and translucent.
Add the garlic to the pot and cook gently for a further 2 minutes stirring often. Avoid burning the onions and garlic as they will give the dish an acrid taste.
Add the celery and carrots. Give everything a good stir to combine all the ingredients together. Cook for 2 minutes more.
Push the vegetables to one side of the pot and cook the mince on a medium heat. The mince needs to become slightly browned. You may need to do this in batches so as not to overcrowd the pot.
Once the meat is browned add the herbs, bay leaf, tomato puree, sugar, salt and pepper. Give everything a good stir to combine.
If you want to add more flavour you can add the optional 125ml of red wine or apple juice at this point. Increase the heat and allow the liquid to bubble for 3 minutes while the alcohol from the wine burns off causing the liquid to reduce slightly.
Now add the tinned tomatoes and beef stock. Allow the mixture to come to the boil.
Once it reaches a boil reduce the heat to medium, pop on a lid and let the whole thing simmer way for 10 minutes. Transfer the lidded pot to an oven that has been heated to 170c fan and cook for 1.5 hours.
While the Ragu is cooking get on with the cannelloni pasta and béchamel sauce.
Turn your oven on to 180c
Allow a boiled kettle of water to cool for 10 or so minutes. Pour the boiled water into a large bowl about one third of the way up.
Place the cannelloni in the water for 30 seconds to a minute. Give them just enough time to soften very slightly. You may need to do this in batches to prevent the bowl being overcrowded and the pasta tubes sticking together. Once softened, place on a clean tea towel or kitchen paper and pat dry to absorb any excess water.
Next make the béchamel sauce. Heat the milk until it is nearly at boiling point. You can do this in the microwave in a microwavable jug or on the stove top in a suitably sized saucepan on a low heat.
While the milk is heating through put the butter into a clean saucepan. On a low heat allow it to melt. Once melted, add the flour and whisk vigorously until combined. Allow the butter and flour mixture to cook gently for a minute. You may see a few bubbles appear and that’s totally fine but don’t let the mixture burn in the pan. Keep stirring.
Gradually add the milk to the butter and flour mixture. Add the milk little by little to prevent any lumps. It should first become a paste and will then thicken as you gradually add more milk.
When you’ve added all of the milk you can increase the heat to medium to allow it to come up to the boil. Make sure you stir continuously to prevent any burning on the bottom of the pan or any lumps forming.
Once it is boiling and has thickened you can turn the heat back down and allow it to bubble away gently for a minute or so. You should now have a creamy, glossy béchamel sauce.
Now you are ready to assemble the dish. Start by spooning a thin layer of Ragu on the bottom of the dish. Begin to fill the tubes with the Ragu sauce using a teaspoon, lining up each tube in the dish as you go.
Once all the cannelloni tubes are filled and placed in the dish pour the béchamel sauce over the top.
Cook in the pre-heated oven for 35 to 40 minutes until golden on top and bubbling.
Serve immediately with a fresh and crunchy salad.