Loaded Cheesy Potato Soup-healthy version

Ingredients

• 4 slices uncured bacon, chopped
• 1 medium yellow onion, peeled and diced
• 5 cups diced Yukon gold potatoes (from about 5 medium potatoes)
• 3 cloves garlic, peeled and minced
• 1 ½ teaspoons coarse salt
• ½ teaspoon ground black pepper
• ½ teaspoon celery salt
• ½ teaspoon ground mustard
• ⅛ teaspoon cayenne pepper
• ¼ cup all-purpose flour
• 4 cups unsalted vegetable stock
• 1 cup milk
• 1 ½ cups shredded mild or white cheddar cheese
• 1 cup shredded sharp cheddar cheese, divided
• Juice of ½ medium lemon
• 3 medium green onions, thinly sliced (optional)