1) Preheat oven to 400ºF
2) Line a large baking sheet with parchment paper.
3) Peel sweet potatoes and slice them into 1/4” rounds.
4) Brush 1 tablespoon of olive oil on the parchment paper. Place sweet potato rounds on it, and brush them with the remaining tablespoon of olive oil and evenly sprinkle with salt.
5) Bake for 30 minutes or until sweet potatoes are soft.
6) While the sweet potatoes are cooking, chop pistachios.
7) Mash goat cheese in a medium bowl add the milk and black pepper and keep mixing until creamy. Add 1/4 cup of the chopped pistachios and mix well.
8) Spread the pistachio goat mixture evenly on each potato round. Sprinkle the remaining pistachios and drizzle with balsamic vinegar, if using.