Prick the sweet potato several times with a fork and microwave for 7 to 10 minutes, until tender.
Allow to cool slightly, remove the peel and mash the flesh with a fork. Set aside.
In a large skillet, heat 1 tablespoon butter over medium-high heat.
Add ½ pound ground pork, 1½ teaspoons chili powder, and ½ teaspoon kosher salt to the pan. Cook the pork, breaking up the meat, until browned, about 3 minutes.
Add 2 minced garlic cloves, mashed sweet potatoes and 1 bunch chopped spring onions to the ground meat. Cook for 2 minutes, stirring constantly.
To the cooked pork, add ½ cup chopped cilantro and season to taste, adding salt if necessary. Transfer the mixture to a bowl and set aside.
Preheat the oven to 200°F.
Wipe out the pan, add half a tablespoon of butter, melt over medium-high heat, and swirl to coat the pan.
Place a tortilla in the pan.
Spread ¼ of the pork mixture on one half of the tortilla.
Sprinkle half a cup of cheese over the pork.
Fold the plain half of the tortilla over the filling and cook for 1 to 2 minutes on each side, until the quesadilla is golden brown.
Place the quesadilla on a baking sheet and place in the oven to keep warm.
Repeat the process to make three more quesadillas.
Cut each quesadilla into pieces. Serve with pickled jalapenos and sour cream, if desired.