In a large saucepan, heat the oil and butter, then add the onions and celery. Sauté gently for 5 minutes until softening, then add the carrots, garlic, herbs and paprika. Cook, stirring, for 10 minutes more until the carrots begin to soften.
Add the tomatoes and stock, bring to a simmer, then add the beans and cabbage. Simmer for 20 minutes until the vegetables are tender.
Pour half into freezer bags, cool, then seal and freeze for up to 6 months. Defrost in the microwave, or put the frozen soup in the pan and reheat. Spoon the other half into 4 bowls, then serve with a dollop of pesto and crusty bread.
