In a large pot or Dutch oven, heat a drizzle of olive oil over medium heat. Add the Italian sausage, breaking it apart with a wooden spoon. Cook until the sausage is browned and cooked through, about 5-7 minutes. Drain excess fat from the pot if necessary. I find that browning the sausage really brings out deep, savory flavors in the soup.

Add the diced onion to the pot with the browned sausage. Sauté for 3-4 minutes until the onion becomes softened. Stir in the minced garlic and cook for another minute until the garlic is fragrant and lightly golden.

Stir in the diced potatoes, mixing them well with the sausage and aromatics. Pour in the chicken broth and bring the mixture to a boil over medium-high heat. Reduce the heat to a simmer and cook for about 15 minutes, or until the potatoes are tender when pierced with a fork.

Once the potatoes are tender, stir in the chopped kale and add the crushed red pepper flakes if you like a touch of heat. Continue simmering the soup for about 5 minutes, allowing the kale to wilt and become tender.

Lower the heat and gently stir in the heavy cream or half-and-half. Season the soup with salt and black pepper to taste. Let the soup warm through for another 2-3 minutes. For an extra touch of richness, I like to use heavy cream, but half-and-half keeps the soup a bit lighter if you prefer.

Ladle the hot soup into bowls and serve immediately. If you like, accompany each bowl with slices of crusty bread for dipping. Enjoy this comforting meal!