In a large pot, heat 2 tablespoons of olive oil over medium heat. Add chopped onions, diced carrots, and bell pepper, sautéing until translucent and fragrant, about 5-7 minutes. Stir in minced garlic and sauté for an additional 2 minutes.

Incorporate the cooked white beans and 4 cups of vegetable broth into the pot, mixing well. Bring to a gentle simmer over medium heat for 2-3 minutes.

Reduce heat to low and let simmer for about 45 minutes for soaked beans, or 15-20 minutes for cooked beans. Keep an eye on the liquid level, adding more broth if necessary.

Blend about 3 cups of the soup until smooth using an immersion blender or regular blender. Return the blended mixture back to the pot, stirring well.

Add chopped kale, dried thyme, and a tahini-harissa mixture to the soup. Simmer on low for an additional 10-15 minutes, stirring occasionally.

Stir in freshly chopped parsley, 1 tablespoon of lemon juice, and season with salt and pepper to taste. Simmer briefly for 2-3 more minutes.

Ladle the soup into bowls, optionally drizzling a mixture of olive oil and harissa on top. Garnish with extra parsley or thyme and serve hot.