Preheat your oven to 400°F (200°C). Puncture the skin of sweet potatoes with a fork and roast for 45 minutes until fork-tender.

In a mixing bowl, combine mashed sweet potatoes, flour, beaten egg, and salt. Mix until a soft dough forms, being careful not to over-knead.

Divide dough into pieces, roll into ropes, and cut into 1-inch sections. Optional: use a fork or gnocchi board to create ridges.

In a boiling pot of salted water, add gnocchi in batches. Once they float (about 2-3 minutes), remove with a slotted spoon.

In a skillet, melt butter over medium heat until golden brown. Add sage, maple syrup, cinnamon, salt, and pepper; stir to combine.

Toss the cooked gnocchi in the brown butter sauce and serve immediately, garnished with Parmigiano Reggiano, walnuts, and fried sage leaves if desired.