Master Recipe 
Please don’t discard those lobster or shrimp shells! They make the base of a rich and delicious stock, seasoned with fennel seeds, star anise, bay leaf, garlic, and a touch of tomato paste for color and a light hint of acidity.
MAKES 2 QUARTS (2 L) BROTH
EQUIPMENT: A 6-quart (6 l) heavy-duty stockpot; a fine-mesh sieve; dampened cheesecloth.
2 tablespoons extra-virgin olive oil
2 pounds (1 kg) lobster or shrimp shells, well rinsed
1 tablespoon fennel seeds
2 whole star anise
4 bay leaves
1 plump, fresh garlic head, halved crosswise
2 teaspoons fine sea salt
1 tablespoon Italian tomato paste
1. In the stockpot, heat the oil over medium heat until shimmering. Add the shells and sear until they turn a bright pink and very fragrant, 2 to 3 minutes.
2. Add the fennel seeds, star anise, bay leaves, garlic, salt, tomato paste, and 3 quarts (3 l) cold water. Bring to a boil and let boil vigorously, uncovered, for 20 minutes. To extract maximum flavor from the shells, use a wooden mallet to gently crush and break up the softened, cooked shells (try not to splash the liquid all over). Taste occasionally for seasoning and strength.
3. Line the sieve with the dampened cheesecloth and place the sieve over a large bowl. Ladle the stock and solids—do not pour—into the sieve, pressing down hard on the solids to extract maximum juices and flavor.
4. Taste for seasoning. Serve warm in small cups as an appetizer or in warmed, shallow soup bowls as a first course. The stock will keep in an airtight container in the refrigerator for up to 1 day or freeze for up to 1 month.