1Melt buter in Dutch oven over med-high heat. Add onion and garlic. Saute til onion is translucent. Do not brown onion or garlic.
2Add asparagus which has been sliced into 1 inch lengths. Saute about 4-5 minutes.
3Add chicken stock and bring to a boil. Reduce to simmer and cook for 30 minutes....until asparagus is very tender.
4Let cool slightly, transfer to blender and puree until smooth. After pureeing return puree to Dutch oven, leaving approximately 1-2 cups in blender. Add potato cubes into blender and blend together. Return potato and asparagus puree to remaining puree in Dutch oven. Season with salt and pepper.
5Add sour cream and half & half to soup mixture in Dutch oven, stirring to mix well. Heat and serve.