In a large Dutch oven, brown the bacon and add the onions, jalapeño and garlic. Sauté for about 4 minutes.
To the Dutch oven, add the potatoes and broth and bring to a boil. Cook until potatoes are tender. Add the milk, 1/2 cup of sour cream (retain the rest to garnish) and spices. Puree with an immersion blender.
Ladle into bowls and garnish if desired with a dollop of sour cream and thin tortilla strips.