Heat butter and oil In a large pot or Dutch oven, over medium heat, until oil starts to shimmer. Add diced onion and sliced smoked sausage and cook about 5 - 7 minutes, stirring occasionally, just until onion is starting to soften and the sausage is getting a little color.
Stir in the garlic, carrots, and baby white potatoes. Add the smoked paprika, cumin, red pepper flakes, salt, and pepper. Stir to combine. Continue cooking for 3 - 4 minutes, stirring several times.
Add the broth and bring to a boil; scraping up any brown bits on the bottom of the pot. Cover pot and reduce heat to medium-low. Simmer 5-10 minutes; add the cubed sweet potato. Simmer an additional 10 - 15 minutes, until the sweet potatoes are tender. Taste for seasoning and adjust as necessary.
Stir in the chopped kale; cook for 1-2 minutes until wilted.