Preheat the oven to 400°F.

Place sweet potatoes on a parchment-lined baking sheet and bake for 45 mins to 1 1/4 hours, or until soft.

Mix flour and salt in a mixing bowl.

Add whole eggs, olive oil, and water to the flour mixture.

Knead into a smooth dough using a mixer with a dough hook.

If too crumbly, add more water; if too wet, add more flour.

Knead the dough by hand on a lightly-floured surface for 8-10 mins until elastic.

Shape into a ball, wrap tightly in foil, and let rest for at least 30 mins.

Remove sweet potatoes from the oven and cool for 10 mins.

Peel the skin off the sweet potatoes and let them cool some more.

Mash the sweet potatoes and season with salt, cinnamon, nutmeg, and cayenne pepper.

Crumble half of the goat cheese and mix it with the sweet potato puree.

Cut the pasta dough in half and wrap one half in foil.

Roll out the other half on a lightly-floured surface to a thin, approximately 16 inch, square.

Cut the dough into 16 4-inch squares.

Put about 1 heaping tsp of sweet potato puree into the center of each square, leaving a margin of about 1/2 inch around the edges.

Brush the edges with egg white.

Fold the opposite corner over the filling.

Press the edges together to seal and transfer the ravioli to a floured baking sheet.

Repeat the process with the remaining dough.

Cook the ravioli in batches in a large pot of generously salted water, simmering for 4-5 mins.

Remove with a slotted spoon and drain well.

Melt the butter in a small pan.

Sprinkle the sage in it.

Distribute the ravioli on plates.

Sprinkle with the remaining goat cheese and the sage butter.