Preheat the oven to 200 degrees. Line the drip pan with parchment paper. Cut the sweet potato and sausage into 1 cm thick slices.
Place the slices on the baking sheet and brush with ghee. Let cook for about 10 minutes. Take out of the oven. First distribute the mustard on the potato slices and then place the sausage slices on top. Sprinkle with cheese and bake for 10 minutes.