Hungarian Chicken Paprikash (Paprikás Csirke)

Ingredients:

• 1 kg (2–2.5 lbs) chicken (thighs or drumsticks)
• 2 tbsp oil or lard
• 1 large onion, finely chopped
• 2 tbsp Hungarian sweet paprika
• 1 tsp salt (or to taste)
• 1/2 tsp black pepper
• 1 bell pepper, chopped
• 1 tomato, chopped (or 1 tbsp tomato paste)
• 200 ml (3/4 cup) water or chicken broth
• 200 ml (3/4 cup) sour cream
• 1 tbsp flour