1

In a heavy—bottomed pot large enough to hold the broth, cook the onion, fennel, and carrot in the oil over medium heat, stirring regularly, for about 10 minutes, or until the vegetables are softened but not browned. Add the shrimp heads and shells, raise the heat to high, stirring often, for about 4 minutes, or until the mixture smells fragrant and the heads and shells turn orange.

2

Let cool for a few minutes. Chop the whole mixture in a food processor for about 30 seconds, or until the shells and heads are broken up but not pureed. Rinse out the pot and return the chopped mixture to it. Add the water and thyme, bring to a gentle simmer, and simmer for 1 hour, skimming off any froth that forms on the surface. Don’t let the broth come to a full boil, or the proteins the shrimp release will cloud the broth. Strain the broth through a fine—mesh strainer and discard the mixture that doesn’t go through the strainer, reserving the shells and heads to make shrimp butter.