Fish Fumet
Fumet is a white stock made from fish bones and aromatic vegetables, which are first “sweated” (cooked until soft but not taking on any color), then simmered in water. That initial step is a crucial building block, eliciting a touch of sweetness from the leek and developing the flavors for the next step, though it will produce a stock with less clarity than when the aromatics are simply brought to a boil with the rest. (To achieve that result, follow recipe for Basic Chicken Stock on page 41, bringing the fish bones and heads to a boil, then adding vegetables, bay leaf, and peppercorns and simmering 30 minutes before straining.) With its concentrated flavor, fumet is ideal for making fish soups and stews, or for steaming shellfish, such as the Clams in Herbed Broth on page 219. Like other stocks, fumet can be altered for different effects. Increase the ratio of bones to water and you will have a stock with more pronounced fish flavor. For a Mediterranean-style stock, chopped garlic and fennel (and its fronds) can be sweated with the other aromatics, then crushed tomatoes, crumbled saffron, and a few parsley stems added and simmered in the pot along with everything else.