Potato Soup With Onions And Cheddar

• 6 skinned varieties such as maine (thin)
• 1 clove garlic (finely minced)
• 1 salt
• 850 gr beef
• 575 gr potatoes see note
• 240 gr pearl onions (peeled)
• 120 ml milk (optional)
• 110 gr sharp cheddar cheese (grated)
• 28 gr butter
• 14 gr parsley divided (finely minced fresh)