Put the pork mince, beef mince, onion, garlic granules, breadcrumbs, egg, dill and salt and pepper into a large bowl and mix well (it's easy to do this using clean hands).
Using damp hands, form 36 walnut sized balls (they will be about 30g each if you want to be exact).
Heat the 1 tbsp of oil in a large frying pan and add half of the meatballs. Stir for 5 minutes to brown and then remove and place on a plate.
Continue with the other meatballs until they are all coloured.
Heat the remaining oil and butter in the same frying pan until melted and add the flour. Heat for 1 minute, stirring (with a small whisk if you have one).
Gradually add the beef stock, stirring well until you have a thick sauce. Add the milk, Worcester sauce, mustard and cranberry sauce (if using) whisk in. (See notes below).
Gently put all the meatballs into the sauce and cover the frying pan with a lid.
Simmer over a gentle heat for 10 - 15 minutes until the meatballs are cooked through (if you have a meat thermometer use it to check them).
Serve 6 meatballs per person and scatter over some extra dill.