Preheat oven to 400 degrees. Poke the sweet potatoes several times with a fork or knife to pierce the skin.
Place on foil or a sheet tray in the oven and bake for 1 hour.
Let yams cool for several minutes, cut in half and scoop out the fluffy insides.
Mash the yams with butter, maple syrup, evaporated milk and salt until creamy and fluffy.
Cut the oranges in half and slice a very thin disk from the bottom so they rest flat. The skins are actually going to be the “bowls”.
With a pairing knife cut around the inside rim of the orange removing the orange sections and pulp. Place any of the orange juice and pulp in a bowl and discard the white membranes and seeds. Save the juice and pulp for cranberry sauce recipe or just enjoy as a snack.
Fill each orange cup with 1/4 cup of puree and top with several mini marshmallows. You can cover and refrigerate these overnight at this point if you're prepping in advance.
Preheat oven to 350 degrees.
Place sweet potato filled orange cups on a sheet tray and bake for 20-25 minutes.
Serve.