Thai Catfish Curry with Sweet Potatoes

Name: Thai Catfish Curry with Sweet Potatoes
Ingredients: 2 teaspoons vegetable oil; 1/3 cup chopped shallots; 1 tablespoon minced peeled ginger; 1 tablespoon minced garlic; 1 1/2 cups reduced-fat (light) coconut milk; 2 to 3 teaspoons Thai red curry paste (see notes); 1 teaspoon firmly packed brown sugar; 2 teaspoons soy sauce; 1 pound Garnet or Jewel sweet potatoes, peeled and cut into 1/2-inch cubes; 1 pound boned, skinned catfish fillets, cut into 2-inch pieces; 3 cups slivered napa cabbage (8 oz.); 3 cups lightly packed spinach leaves, rinsed; 1/4 cup chopped fresh cilantro; 2 tablespoons lime juice