A Puerto Rican shrimp broth.
Heat the oil in a large stockpot over medium-high heat. Add onion and chiles and fry until softened.
Add the sofrito, shrimp shells, garlic, salt, cilantro, and thyme. Continue frying for a few more minutes. {Editor's note: to what end?}
Add the water and simmer for 15 minutes. Remove from heat and let cool.
Strain the broth, removing solids.