Slow Cooker Potato Soup Recipe

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