Cheese Potato Chowder

• 1 1/4 instant mashed potato flake
• 700 ml low-fat milk
• 240 ml chicken broth
• 90 gr onion (chopped)
• 65 gr green bell pepper
• 45 gr crumbled bleu cheese
• 38 gr sharp cheddar cheese
• 14 gr butter
• 1 gr black pepper (ground)