Roast the peppers in the oven for around 30 minutes, turning occasionally, until the skins are blistered and blackened in places. Alternatively, roast them over hot coals for a smoky flavour.
Transfer the hot peppers to a bowl and cover. Leave them to steam while you prepare the chicken.
Season the chicken with salt and black pepper. Heat a little vegetable oil in a large, deep pan and brown the chicken on all sides. Remove from the pan and set aside.
Finely chop the onions and add them to the same pan. Cook over medium heat until softened.
Peel the roasted peppers, remove the stalks and seeds, and slice the flesh into strips.
Add the roasted peppers and finely chopped garlic to the onions. Cook for another 1 to 2 minutes, stirring gently.
Add the chopped tomatoes, tomato paste and one can of water, using the empty tomato tin to measure. Stir in the sweet paprika and season with salt and black pepper.
Return the browned chicken to the pan. Bring the sauce to a gentle simmer, cover with a lid and cook for around 30 minutes, or until the chicken is cooked through and tender. Stir occasionally and add a little more water if the sauce becomes too thick.
Turn off the heat and gently stir in the sour cream until the sauce is smooth and creamy.
Taste and adjust the seasoning if needed. Garnish with fresh parsley, if desired, and serve hot with mashed potatoes or fresh bread.