Sauté finely-chopped onion and garlic in butter and oil until transparent. Add sliced green pepper, then the coarsely-chopped tomatoes and cook, stirring continuously, for a minute or two. Season to taste with sugar, salt and pepper, and simmer for 30 minutes.
Sauté veal escalopes in a little butter in a frying pan until cooked through. Arrange on a hot serving platter and keep warm. Stir dry white wine into pan juices and cook over a high flame until sauce is reduced by half. Add cooked tomato, pepper and onion mixture; pour in cream and simmer sauce gently for 5 minutes. Whip butter into the sauce and pour over escalopes. Sprinkle with parsley and serve immediately.