Garlic Parmesan Scalloped Potatoes

butter

minced garlic ((or 4 large garlic cloves, minced))

all-purpose ((or plain) flour)

milk ((skim, 2% or full fat -- more if needed))

chicken bullion powder ((or Kosher salt))

Salt (, to taste)

black pepper

| 1 1/2 kgs potatoes (, peeled and sliced into 1/8-inch rounds)

shredded mozzarella cheese

Parmesan cheese ((freshly grated))

fresh chives (, divided)