This sauce which is in a bean base, provides lots of fiber and a creamy texture to the tortellini.
Cover the beans with water and soak for at least 8 hours or overnight. Drain.
In a non-stick pan, heat olive oil over medium heat. Add the onion and cook, for 3 minutes. Mix in the garlic and cook for another minute. Add the tomatoes and tomato paste, stir and cook for a few minutes. Add chicken broth, bay leaf and beans and bring to a boil, reduce the heat and simmer, uncovered, for 1 1/2 hours.
Pour the bean mixture into a blender or food processor and process into a puree. Adjust the consistency with more stock if necessary.
Bring large pot of salted water to boil. Cook tortellini according to package directions.
Pour sauce over tortellini garnish with basil and serve.