Put the bacon lardons into a cold pan over a medium low heat and allow the fat to render out for around 10-15 minutes. Stirring occasionally.
Add the diced veg, a little splash of olive oil and season lightly. Add the bay and rosemary and continue to cook the veg, stirring often, until softened, about 12-15 minutes.
Add the beef mince and season again. Continue to cook, stirring regularly until the meat has begun to brown- about 8-10 minutes.
Add the tomato puree and cook out until everything is brick coloured- about 4-5 minutes.
Add the white wine and turn the heat up to medium high- we want the wine to deglaze the pan and pull off that beautiful fond that is getting stuck to the bottom of the pan, so use a wooden spoon to scrape this away and into the mix.
Once the wine has almost completely reduced, add the milk and allow to reduce down to almost nothing as well.
Add the tinned tomatoes and break them up with a spoon before adding about 300g of water or stock. Stir to combine and check the seasoning again.
Bring to a simmer before adding the basil and parmesan rind and leave to blip away for at least 2 hours, topping up with stock or water as needed.
Remove the parmesan ring and herbs, give the seasoning one final check and leave to cool completely- we want the ragu to be fridge cold before filling our calzone.
To make the calzone, open up a 230-250g Neapolitan dough ball into a pizza skin- slightly smaller than you would for a pizza as we don’t want it too thin!
Spoon in a line of ragu across the centre- around 4-5 tbsp, and top with a couple of basil leaves and mozzarella. Make sure to leave border of around 4cm around the outside.
Fold the dough over towards you and use the butt end of a pizza wheel to stick the dough together all the way round- it should look like a classic calzone or Cornish pasty at this point!
Cut the excess dough away from the crimped edge so you’re left with a beautiful looking sealed parcel and pierce the top 2 or 3 times with a skewer to allow the steam to escape.
Turn a preheated, hot Roccbox flame down to its lowest setting before popping the calzone onto a floured peel and launching into the front third of the oven.
Bake for 2 1/2 – 3 minutes rotating and turning as required.
When the calzone comes out the oven, grate over a little parmesan and get stuck in!