Heat 1 tablespoon of olive oil in a large pot over medium heat. Add the sliced kielbasa and cook until browned on both sides. Remove the kielbasa from the pot and set aside.

In the same pot, add the remaining olive oil. Add the diced onion, carrots, and celery. Sauté until the vegetables are softened, about 5 minutes.

Add the minced garlic and cook for another minute until fragrant.

Pour in the chicken broth and bring the mixture to a simmer. Add the cannellini and Great Northern beans, thyme, and bay leaf. Season with salt and pepper to taste.

Return the kielbasa to the pot. Let the soup simmer for about 15-20 minutes, allowing the flavors to meld together.

Remove about 2 cups of the soup (make sure to get mostly beans and some broth) and blend until smooth using a blender or an immersion blender. Be careful when blending hot liquids.

Return the blended mixture to the pot and stir well. This will thicken the soup and give it a creamy texture.

Stir in the heavy cream and let the soup cook for another 5 minutes on low heat. Check for seasoning and adjust if necessary.

Remove the bay leaf before serving.

Ladle the soup into bowls and garnish with chopped fresh parsley. Serve hot with crusty bread on the side for a complete meal.