Slow-Cooker Manhattan-Style Shrimp Chowder

Heat the oil in a large nonstick skillet over medium-high. Add the fennel, leek, celery and garlic to the skillet; cook, stirring occasionally, until the vegetables are softened and lightly caramelized, 6 to 8 minutes. Add the wine to the skillet; cook 1 minute, stirring and scraping to loosen the browned the bits from the bottom of the skillet. Transfer the mixture to a 5- to 6-quart slow cooker.

Stir the tomatoes, potato, water, clam juice, salt and saffron threads into the slow cooker. Cover and cook on LOW until the potato is tender, 5 to 6 hours. Increase the slow cooker heat to HIGH; stir in the shrimp. Cover and cook until the shrimp are done, 5 to 7 minutes. Ladle the chowder into bowls and serve hot.