Potage Parisienne, From "la Tour" Restaurant

• 2 potato (raw diced)
• 1/2 cu
• 1,400 ml chicken stock
• 240 ml cream i use (heavy)
• 75 gr leek potatoes (yellow)
• 65 gr flour
• 28 gr butter
• 7 gr onion (finely chopped)
• 1 gr parsley (finely chopped)