Baked Potato Soup with Bacon & Cheddar Cheese

Ingredients

• 12 slices bacon -- cut into 1/2-inch pieces
• 2/3 cup salted butter
• 2/3 cup all-purpose flour
• 7 cups whole milk
• 4 large Russet baking potatoes -- peeled and cubed (roughly 2 - 2 1/4 pounds)
• 4 green onions -- chopped (plus more for garnishing)
• 1 1/4 cups grated cheddar cheese -- plus more for garnishing
• 1 cup sour cream -- plus more for garnishing
• 1 teaspoon Kosher salt
• 1 teaspoon freshly ground black pepper