In a large, heavy-bottom saucepan, melt the butter over medium-low heat.
Add the onion and sauté for about 10 minutes, until soft and translucent.
Stir in the flour, letting it cook for about 30 seconds like a roux.
Stir in the sugar, salt, pepper, garlic, oregano and curry powder.
Slowly stir in the tomato juice.
Increase the heat to bring the soup just to a boil, and then taste, adjusting the seasonings as needed, and serve.
