Slow Cooker Loaded Potato Soup

medium russet potatoes, peeled (optional) and cut into small cubes

stalks of celery, chopped

onion, diced

vegetable broth

garlic, minced

butter

sharp cheddar cheese, grated

salt

ground black pepper

garlic powder

red pepper flakes

milk (I used 2% but you could also use cream, half and half, or skim)

freshly grated cheddar cheese (for topping)

chopped green onion (for topping)