Sup Kentang Merah

Bahan-bahan (10 porsi)

• 1 (12-ounce) package smoked bacon, (chopped)
• ½ cup bawang bombay potong dadu
• 2 stalks seledri potong dadu
• 1 large wortel potong dadu
• 2 teaspoons bawang putih cincang
• 2 pounds red potatoes, (cubed)
• 6 cups kaldu ayam
• ⅔ cup mentega tawar
• ¾ cup all-purpose flour
• 4 cups whole milk (at room temperature, divided)
• 1 (8-ounce) container sour cream
• 2 ½ cups shredded sharp cheddar cheese, (divided)
• garam dan merica (secukupnya)
• daun bawang atau daun bawang untuk hiasan