Ingredients

• 1 tablespoon olive or canola oil
• 4 cups shrimp heads and shells
• 1 onion, quartered with skins on
• 1 large carrot, cut into chunks
• 1 celery stalk, cut into chunks
• 3 cloves garlic, pounded
• 2 bay leaves
• 1/2 teaspoon peppercorns
• 6 cups cold water