Wash the potatoes with water. Then pierce the potatoes with a fork and microwave potatoes for 13 minutes on high.
As the potatoes cooks, heat oil in a large pot over medium-high heat. Add onion and garlic; sauté for 3 minutes. Then add chicken broth and mix well.
In a small bowl combine the flour and 1/2 cup milk and mix well. Then add the
Add milk and flour mixture to pot then add in 1 1/2 cups milk.
Bring to a boil, stirring often. Once at a boil cook for about a minute, add in potatoes, the sour cream, salt, and pepper and mix well.
Using a potato masher mash the cooked potatoes and then add them to the soup. Mash until the consistency of potatoes that you want or you can use an immersion blender.