In large pot over medium heat, cook sausage until browned and cooked thoroughly. Remove from pot and drain on paper towels.
In same pot, melt butter and saute onions until softened, about 5 minutes. Stir in garlic and cook until fragrant, another minute. Stir in cooked sausage and flour. Cook 2 minutes to cook out the raw flour taste. Add in chicken broth and seasonings. Bring to boil, then reduce to simmer. Stir in kale and potatoes. Cover and cook 10-15 minutes or until potatoes are tender.
When ready to serve, remove the bay leaf and add in heavy cream.