1.Place bean mix in a medium saucepan; cover with 5cm cold water. Bring to the boil over medium-low heat. Boil about 5 minutes; drain. Transfer beans to a 4.5-litre (18-cup) slow cooker.
2.Heat butter and oil in a large frying pan over medium heat; cook onion, carrot, celery and garlic, stirring, for 5 minutes or until softened. Add wine; bring to the boil. Boil until wine has almost evaporated. Add paste, tomatoes, stock, salt, sugar and thyme. Transfer to cooker. Cook, covered, on low, about 8 hours. Season to taste.
3.Discard thyme. Stir in spinach until wilted. Sprinkle ragù with parmesan to serve.