Heat the oil in a large non-stick saucepan or casserole dish and fry the onions over medium heat for 6—8 minutes until softened and lightly coloured, stirring regularly.
Put the chicken on a board and cut away any visible fat.
Cut each thigh in half, season with ground black pepper and add to the pan.
Cook the chicken with the onions for 4—5 minutes until lightly coloured on each side.
Stir in the garlic and paprika and cook for 1 minute more.
Tip the tomatoes into the pan, pour over the chicken stock and add the bay leaves and mixed herbs.
Bring to a gentle simmer, then cover the pan loosely with a lid and cook for 20 minutes, stirring occasionally.
Cut the peppers in half and deseed and cut into chunks.
Add to the chicken and cook everything for another 25—35 minutes, occasionally stirring, until the chicken is tender.
Mix the cornflour and water to make a smooth paste and stir this into the pan.
Cook for 2—3 minutes until the sauce is thickened, stirring constantly.
Serve the paprika chicken topped with a little half-fat creme fraiche.