In a casserole, put the potatoes cut into chunks, together with the other vegetables in 6 tablespoons of oil. Bring gently to the boil and then add about a litre and a half (2 1/e pints or 6 3/4 cups) of water, salt, pepper, and the white wine.

Simmer for about an hour, adding 2 tablespoons of oil half-way through.

Pass through the vegetable mill and return to the heat for twenty minutes more.

Toast the bread slices, dice (if you wish, the bread cubes can be fried in olive oil) and put in each persons's bowl. Dust generously with Parmesan cheese.