1 pound bulk Italian sausage
4 cups half-and-half
3 cups cubed potatoes
2 cups low-sodium chicken broth
2 cups whole milk
1 onion, chopped
1/2 teaspoon dried oregano
1/2 teaspoon red pepper flakes, or more to taste
1/2 teaspoon ground black pepper
2 cups torn kale leaves (bite-size pieces)
Heat a large soup pot over medium-high heat. Crumble sausage into pot; cook and stir until browned, about 10 minutes. Drain and discard grease.
Stir half-and-half, potatoes, chicken broth, milk, onion, oregano, and red pepper flakes into sausage, bring to a boil, and reduce heat to low. Simmer until potatoes are tender, about 30 minutes. Season with black pepper; stir kale into soup. Simmer until kale is tender, 10 to 15 more minutes.