1. Heat 3 tablespoons olive oil in a large Dutch oven over medium-high heat. Generously season chicken thighs with salt and pepper; add chicken to Dutch oven and cook, turning once, until deep golden brown, about 8 minutes per side. Remove chicken from Dutch oven and set aside.

2. Add remaining tablespoon olive oil to Dutch oven, if necessary. Add onions and season with salt and pepper. Cook, stirring, until golden, about 10 minutes. Add peppers and cook, stirring, until softened, about 5 minutes. Return chicken to Dutch oven and sprinkle chicken and vegetables with paprika. Add tomatoes and 3/4 cup water; bring to a boil. Cover and let simmer until chicken is very tender, about 40 minutes.

3. Remove Dutch oven from heat; remove chicken from Dutch oven and keep warm. Using an immersion blender, blend vegetables and cooking liquid until smooth. Whisk in sour cream and season with salt and pepper. Return chicken to Dutch oven and keep warm until ready to serve. Garnish with parsley and additional sour cream, and serve with nokedli and cucumber salad.