Slow Cooker Potato Soup

Name: Slow Cooker Potato Soup
Prep time: 10 min
Cook time: 4 h 10 min
Total time: 4 h 20 min
Cuisine: American
Ingredients: 6 slices cooked bacon* (diced); 3-4 cups good-quality chicken or vegetable stock; 2 pounds Yukon gold potatoes** (peeled (if desired) and diced); 1 medium white or yellow onion (peeled and diced); 4 tablespoons bacon grease* (or butter); 1/3 cup all-purpose flour; 1 (12-ounce) can 2% evaporated milk; 1 cup shredded reduced-fat sharp cheddar cheese; 1/2 cup plain low-fat Greek yogurt or low-fat sour cream; 1 teaspoon Kosher salt (or more to taste); 1/2 teaspoon freshly-cracked black pepper; optional toppings: thinly-sliced green onions or chives (extra shredded cheese, extra bacon, sour cream)