Prep the sweet potatoes: Preheat your oven to 375°F (190°C). Wash the sweet potatoes thoroughly, scrubbing the skin to remove any dirt. Pat them dry with a clean towel.
Pierce each sweet potato a few times with a fork to allow steam to escape during baking.
Place them directly on the oven rack or a baking sheet lined with parchment paper. Bake for about 50–60 minutes, or until they’re soft when pierced with a knife.
Prepare the filling ingredients: While the sweet potatoes are baking, dice the smoked ham into small pieces. Heat a small skillet over medium heat and add a pinch of oil (approximately 1/2 tsp). Add the diced ham and toast until slightly crispy, about 3–4 minutes. Remove from heat and set aside.
Scoop out the sweet potato flesh: Once the sweet potatoes are done, carefully remove them from the oven and let them cool for about 10 minutes.
Cut each sweet potato in half lengthwise. Use a spoon to gently scoop out the flesh, leaving a thin layer around the skin to help maintain the structure. Place the scooped-out flesh into a large mixing bowl.
Mix the filling: Add the Greek yogurt, salt, white pepper, toasted ham, and half of the Parmesan cheese to the sweet potato flesh. Mash everything together with a fork or potato masher until smooth and well combined. Adjust the seasoning if necessary.
Refill the sweet potato skins: Spoon the mixture back into the sweet potato skins, dividing it evenly among the six halves. Place them back onto the baking sheet.
Bake again: Sprinkle the remaining Parmesan cheese evenly over the tops of the filled sweet potatoes. Return them to the oven and bake at 375°F (190°C) for an additional 15 minutes, or until the tops are golden and slightly crisp.
Garnish and serve: Remove the sweet potatoes from the oven and garnish each with a pecan on top. Serve warm as a side dish or light meal.