Schiacciatine (a hamburger version from the South of Italy)

Difficulty:  Time:  INGREDIENTS (x 12 small burgers): - 500 g lean minced beef meat - 2 big slices sourdough bread (about 150 g) - 250 ml milk - 1 egg - 1 garlic clove, thinly chopped (optional) - 1 handful of grated parmesan - 30 g grated mature English Cheddar cheese - 80 g plain breadcrumbs - 1 large handful of parsley, finely chopped - ...