Place diced sweet potato in a small saucepan and add enough water to just barely cover it. Season with a little salt. Bring to a boil then lower heat and simmer until tender. Drain well, mash, and add 1 tablespoon butter and chipotle sauce.

Heat a non-stick skillet over medium-high heat and add a little butter or oil. Cook the onion, stirring frequently, until it starts to soften and even blacken a little on the edges. Remove from pan and set aside. (Can also briefly cook the apple slices, too, if desired.)

Lay four of the tortillas out on a flat surface. Spread about 1/3 cup of the sweet potato mixture onto each of the four tortillas in a thin, even layer. Next top with a few slices of apple and onion. Sprinkle each one with a little ground cinnamon, dot the filling with 1/4 cup goat cheese, and top with another tortilla.

Heat a non-stick skillet again over medium-high heat and add a little oil or butter. Swirl to coat the bottom of the pan. Carefully lift one of the quesadillas into the skillet. Let cook until lightly browned on the bottom. Carefully turn over and cook the remaining side until golden brown. Repeat with the remaining quesadillas, adding a little oil to the pan before each one.

Cut into wedges and serve.