Add the chopped bacon to a cold, medium to large saucepan and set over medium-high heat. Cook, stirring occasionally, until the bacon is crispy and the fat has rendered.
Add the diced onion to the saucepan with the crispy bacon and sauté for a few minutes until the onion softens and becomes translucent.
Stir in the cubed potatoes, trimmed green beans, dried savory (or marjoram), a generous pinch of salt and pepper, and the stock. Mix well to combine all ingredients.
Bring the soup to a boil, then reduce heat and simmer gently until the potatoes and green beans are fully cooked, about 20–25 minutes. This lets the flavors meld together nicely. I always taste as it simmers and adjust seasoning if needed.
Transfer about one third of the cooked soup to a bowl. Use an immersion blender to blend it until smooth. Add the room temperature sour cream and continue blending until fully mixed. This creates a creamy base for the soup.
Pour the puréed mixture with sour cream back into the pot. Stir well to combine with the rest of the soup. Gently reheat for a few minutes, but do not let it boil, to prevent the sour cream from curdling.
Remove the soup from heat and ladle it into serving bowls. Garnish with parsley or extra bacon bits if desired and serve hot.