Heat the oil in a large skillet over medium heat and brown the sliced sausage, then remove from pan
Add in the sweet potato, salt and onion and cook for about 10 minutes, stirring occasionallyYou want to get a little color on the sweet potato and it should be just starting to get tender
Then add in the diced green apple and spinach. Continue to sauté until spinach is wilted and potatoes are tender
Stir in the cooked sausage and lemon juiceTaste for seasoning and serve