Heat 2 tablespoons of oil in a large pan and fry the onions for 2-3 minutes. Add the turnips, and fry for a further 2 minutes at a medium heat.
Add the white wine, and season with salt and white pepper to taste. Stir well, then add enough water to cover the vegetables.
Bring the water to the boil and add 1 mashed clove of garlic. Cover, and cook for 15 minutes at a low heat.
Remove the lid, and blend the soup to a creamy consistency.
For the garlic toast, heat 2 tablespoons of oil in a pot and add 1 mashed clove of garlic. Fry for 1 minute. Add 2 slices of bread, and fry it until golden brown.
Serve with a pinch of parsley and the garlic toast on the side.