Place bread cubes in a bowl and pour the milk in. Soak for 5 mins, then squeeze the milk in excess out of the bread with your hands, before adding to the meat mixture.
In a large bowl combine ground beef with parmesan, parsley, bread cubes, chopped rosemary and egg. Mix well with your hands, then season generously with salt and pepper.
Heat a large skillet over low-heat with 1 tbsp of oil. Add onion and cook until soft. Add mushrooms and cook for 5 mins, over med-heat. Remove from the pan and allow to cool.
Fold onion and mushrooms into the beef mixture. Combine well, then form meatballs with your hands. Place flour into a plate, then roll each meatball until evenly covered.
Return the skillet over med-heat, and add the butter in. Then fold the meatballs in and cook for 2 mins.
Turn the meatballs and cook for a further 2 mins. Pour the wine in and allow the alcohol to evaporate. Add stock, season with a pinch of salt, cover with a lid and cook for 10-15mins.
Meanwhile make the bruschetta: Rub against each bread slice the garlic clove. Brush with melted butter, sprinkle with parsley and season with salt and freshly cracked black pepper.