Creamy Cannellini Soup

Bahan-bahan (6 porsi)

• 1 onion (diced)
• 2 ribs celery (chopped)
• 8 ounces Italian sausage
• 1 russet potato (peeled and chopped)
• 1 teaspoon Italian seasoning
• 30 ounces canned cannellini beans (2 x 15 oz cans, drained and rinsed, divided)
• 4 cups chicken broth (divided)
• 1 tablespoon pesto (more to taste)
• 1 tablespoon shredded Parmesan cheese
• chopped fresh parsley