Preheat oven to 400ºF. Carefully, pierce holes in sweet potato with a fork. Place sweet potatoes on a sheet pan and bake until sweet potatoes are fork-tender, about 45 minutes. Cut open the sweet potatoes, and remove the flesh. Mash together well until smooth. Measure out 3 cups of sweet potatoes. Set aside any remaining for another use.
In a medium mixing bowl, mix together the 3 cups mashed sweet potato, almond flour, tapioca flour, egg, and salt. The dough should be slightly sticky but not so sticky that you can't roll it into balls in your floured hands. If it is too sticky, add in a tablespoon more tapioca flour at a time.
Lay a sheet of parchment paper down to work on and sprinkle it with tapioca, and sprinkle some tapioca on your hands.
Gather the dough into balls (about 1 1/2 inches or so), and feel free to sprinkle with more tapioca flour as needed.
Roll it out into long logs, sprinkling with more tapioca as needed to prevent sticking and cut into 1” pieces.
Roll 1” pieces over a fork lightly to make an indent, or skip this step and leave the gnocchi as is.
Fill a medium pot with water and a big pinch of salt and bring to a boil.
Work in batches, place gnocchi into the boiling water. Do not overcrowd the pot.
Your gnocchi is done cooking when they float to the top and stay there for 20 seconds or more.
Remove with a slotted spoon and place on a dish. Repeat with remaining gnocchi.
Heat oil in a large skillet over medium-high heat. Once hot, add gnocchi in batches, and cook until lightly golden. Flip the gnocchi and continue to brown on the other side. Remove gnocchi to a plate, and repeat with any remaining batches.
Once all gnocchi is browned. Add butter to the pan. Cook until the butter browns slightly. Add in spinach, sage, sea salt, and pepper and cook until spinach wilts. Add gnocchi back to the pan to heat through. Taste and adjust seasoning and serve gnocchi with a shaved parmesan cheese, if desired.