Using cooking spray, spray the crockpot.

Toss onion, garlic, potato, and broth into the crockpot.

Cook on low flame for six to eight hours or on high flame for four hours, stirring occasionally.

Mix the cheese, bacon, and green onions about 15 minutes before serving.

Whisk together the milk and cornstarch in a separate small bowl. Pour into the soup and simmer for about 15 minutes, stirring frequently.

Serve topped with fresh herbs or cheese.