Thoroughly combine beef mince, rice, milk, egg, garlic, basil and salt in a bowl. Form the mixture into about 16 small meatballs.
Heat olive oil in a frypan over medium heat and brown the meatballs well on all sides, about 15 minutes.
Place the spaghetti sauce, diced tomatoes, beef stock, red wine, basil, cayenne pepper, bay leaves and 3 minced garlic cloves in slow cooker, and stir to combine. Put the meatballs into the slow cooker and stir gently to cover with sauce. Shake the frozen vegetables over the sauce, without stirring and cook on Low, covered, for 6 to 8 hours, until the meatballs are tender and the vegetables are cooked.
About an hour before serving, gently stir the sauce, being careful not to break the meatballs, and remove the bay leaves. Cook for 1 more hour to blend the flavours and thicken the sauce.
We are garlic lovers, and slow-cooked garlic is good but subtle. I like to add two additional cloves of garlic to the sauce about 30 minutes before serving to give it a bolder garlic flavour.
You can substitute fresh red and green capsicums and yellow onion, cut into strips, for the frozen stir fry mix.