VEGETABLE STOCK can be made more quickly than those made with meat and bones, because extracting flavor from bones takes a long time. To get the most flavor out of vegetables in a shorter cooking time, they should be coarsely chopped into small pieces. Do not boil or cook too long, for the smaller pieces can break up and make the stock cloudy.
The object in making a light vegetable stock (fonds blanc) is to have subtle, not overpowering, vegetable flavors. For this reason I remove the dark gills from the mushrooms (though they are fine in a brown vegetable stock; see Variation). And although I encourage you to try other vegetables here, I also recommend that you avoid the strong tastes of turnips and members of the cabbage family.