1. Place raisins in a small bowl; cover with hot water. Let stand 5 minutes or until plump; drain.
2. Heat oil in a Dutch oven over medium heat. Add onion to pan; cook 10 minutes or until tender, stirring occasionally. Add about one-fourth of spinach to pan; cook 3 minutes or until spinach wilts, stirring occasionally. Repeat procedure 3 times with remaining spinach. Stir in raisins, nuts, salt, and pepper.