Preheat oven to 400 degrees Fahrenheit. Prick sweet potatoes with a fork and rub all over with olive oil, salt and pepper and place in a 13×9 baking dish or lined sheet pan. Bake for 50-60 minutes until tender.
Add a swish of olive oil to a medium skillet over medium-high heat. Cook the Italian sausage until browned, remove to a paper towel-lined plate, leaving just a little grease behind. If there isn’t much grease, add a bit of olive oil. Add the onion and sauté two minutes, until translucent. Add the apple, sage, salt and pepper and continue sautéing until everything is softened and fragrant, about 5-7 minutes. Return sausage to the mixture and deglaze the pan with a big splash of white wine, scraping up all the flavorful browned bits. If you don’t have wine on hand you could use chicken broth or water, or simply skip this step.
Slice the sweet potatoes in half lengthwise, cutting almost all the way through but leaving peel connected. Use a butter knife or fork to slightly mash or break up the sweet potato flesh. Add a big scoop of filling to each potato and sprinkle with mozzarella cheese. Return to the oven for a few minutes until the cheese is melted.
Garnish with fresh parsley and/or balsamic glaze!
