In a large pot, heat olive oil over medium heat. Add in Italian sausage, breaking it apart. Sauté for about 7-8 minutes until browned and cooked through. Remove sausage and set aside, leaving drippings in pot.

Add diced onion to the pot and sauté for about 5 minutes until translucent. Stir in minced garlic and cook for another 1-2 minutes until fragrant, scraping up bits from the bottom.

Pour in chicken broth and bring to a gentle boil. Add diced potatoes. Reduce heat to a simmer and cook for approximately 15 minutes until potatoes are tender.

Return cooked sausage to the pot along with chopped kale. Stir and let it simmer for another 5 minutes.

Reduce heat to low and stir in heavy cream. Season with salt, black pepper, and red pepper flakes to taste. Warm for an additional 3-4 minutes without boiling.

Ladle soup into bowls and sprinkle with grated Parmesan cheese. Serve warm.