Heat the olive oil in a large skillet over medium-high heat. Add the sausage and cook, breaking it into pieces with a wooden spoon, for 2-3 minutes until browned.
Add the onion and garlic to the skillet and cook for 1-2 minutes until the onion softens.
Transfer the sausage mixture to the slow cooker. Stir in the broth, vinegar, adobo seasoning, salt, thyme, pepper, rosemary, and sweet potatoes. Cover and cook on low for 6 hours (or high for 3 hours).
Remove and discard the rosemary sprig. Scoop out 1 cup of the sweet potato mixture (avoiding sausage), blend until smooth, and return it to the pot. Stir in the cream if using.
Add the kale, switch to high heat, and cook for another 10-15 minutes until the kale is tender. Serve immediately.
Use the sauté function to brown the sausage mixture. Add all other ingredients with 5 cups of broth and pressure cook for 10 minutes. Let the pressure release naturally and follow the blending and kale steps above.