In a medium frying pan heat 2 tablespoons oil over medium heat and add the onions and green peppers. Cook, stirring often until they start to soften.Turn the heat down to low and push the onions and pepper to the sides of the pan making a well in the middle. Add another tablespoon of oil and both paprikas. Stir the vegetables into it and cook 2 - 3 minutes. If the pan is very dry add the remaining tablespoon of oil.Scrape it into a 4 or 5 quart crockpot with the tomatoes, salt and pepper.In a large bowl using a fork combine the beef, egg, bread crumbs, onion, parsley, salt and pepper.Scoop up rounded tablespoons of the mixture and form into balls. Gently drop into the sauce.Cook on high for 4 hours or low 5 - 6 hours. Add the sour cream to a medium bowl and mix in a few ladles of sauce to temper it then pour the entire thing back into the pot and stir well.Serve over egg noodles, rice or mashed potatoes.