Preheat oven to 425 degrees F.
Line a large baking sheet with foil and spray with a nonstick cooking spray. Set aside.
Clean and dry the bell peppers. Cut them in half and remove the seeds and membranes.
Place the bell peppers cut side down on the baking sheet, pressing them down to make them as flat as possible.
Bake the bell peppers for 20-25 minutes until skin is blackened and peppers are soft. Remove from the oven and place the peppers inside a container that has a lid. Seal the peppers inside. This will allow the steam to soften them more. Keep in there for another 15 minutes.
In a dutch oven, saute the onions with the olive oil until the onions are soft and translucent. Add the garlic and cook an additional 30 seconds. Remove from the heat.
After peppers have cooled enough to touch, about 15 minutes. Remove from the container and peel off the burnt skin. (I only peeled the burnt parts that were easily removed and left the skin that was still red and attached).
Place the bell pepper, onion and garlic into a food processor or blender and blend until smooth.
Add the red pepper mixture back to the dutch oven and heat over medium heat. Pour in the chicken stock and add the salt, crushed red pepper, dried thyme, and black pepper. Bring to a simmer, cover and allow to simmer for another 20 minutes.
Remove from the heat. Stir in the sour cream. Place the oregano in your hand and crush it up slightly to release the flavor and to make the pieces smaller, then pour into the pot. Stir until completely combined.
Serve with extra sour cream and fresh herbs on top if desired.