Heat olive oil in a large stockpot or Dutch oven over medium heat. Add Italian sausage and cook until browned, about 3-5 minutes, making sure to crumble the sausage as it cooks; drain excess fat.
Stir in garlic, onion, oregano, basil and red pepper flakes. Cook, stirring frequently, until onions have become translucent, about 2-3 minutes; season with salt and pepper, to taste.
Stir in chicken broth and bay leaf, and bring to a boil. Add potatoes and cook until tender, about 10 minutes.
Stir in spinach until it begins to wilt, about 1-2 minutes. Stir in heavy cream until heated through, about 1 minute; season with salt and pepper, to taste.