Place all of the meatball ingredients into a large bowl (apart from the mozzarella) and combine together using your hands. Place in the fridge whilst you prep the tomato sauce.
In a large pan, heat a glug of oil over a medium heat and put in the garlic and chilli. Let them cook for a couple of minutes until they start to soften. Then add in the rest of the ingredients for the sauce. Turn the heat up to medium high until the sauce starts to boil. Turn it down slightly so that the sauce is on a steady simmer. Leave to simmer for around 30mins until it has reduced.
Take the meatball mixture out of the fridge. Grab a golf ball size piece of meat and flatten it in your hand. Pop a cube of mozzarella in the middle and work the meat up and around the cheese until it is covered. Repeat until you have 12 little meatballs. and pop them back in the fridge.
Pre heat the oven to 200º.
Lightly oil a muffin tin. Take a sheet of filo pastry and brush with a little beaten egg. Sprinkle over a little grated cheese (don't be tempted to over do the cheese!) and place another layer of filo on top and press down. Cut the filo into squares, large enough to fit into the individual muffin moulds in your tray. Place the shares into the moulds making sure they are pressed in. You can use a circular cookie cutter to ensure more even pastry cases, but I quite like the hotch potch nature of the squares! Pop in the oven for 10minutes and leave to one side once cooked.
Line a tray with silver foil and place the meatballs in the oven for 20mins.
Back to the sauce! By this time most of the liquid will have evaporated. Using a hand blender, brake down any large bits of tomato and pepper so that you are left with a smooth sauce. You want a really thick sauce, so keep cooking it until very little liquid is left.
Now to plate them up! In each filo case, add a meatball, make sure it is well pushed in, not resting on the top! Then add a small spoonful of the tomato sauce. You really don't need much as it is so concentrated.