Heat the olive oil in a large pot over medium heat. Add in the diced onion, saute for 5 minutes until softened, then add in the minced garlic and saute for another minute or so until fragrant.
Add in the rest of the ingredients, except for the sour cream, and turn the heat up to medium-high. Stir to combine and cook for 25-30 minutes, until cooked through and slightly thickened.
Place the 2 tablespoons of sour cream in a small container and add in a few spoonfuls of broth from the stew. Whisk together to temper the sour cream (this makes sure that the sour cream doesn’t clump when added to the stew).
Add in the tempered sour cream to the stew and stir to combine. Taste for seasoning and spoon into bowls.