Make the Gnocchi

1. Wash and pierce the sweet potatoes all over with a fork, wrap in damp paper towels and microwave on high for 20-30 minutes, or until very soft. Then, halfway through microwaving, re-dampen the paper towels and turn over the sweet potatoes.
2. When sweet potatoes are cool enough, peel and mash potatoes in a medium bowl until smooth.
3. Stir in ricotta cheese, salt and pepper, then mix in flour with a fork until dough forms. Dough should be loose and not sticking to the sides of the bowl. If dough is too sticky, add more flour, one tablespoon at a time.
4. In a large pot, bring a gallon of water to a boil over high heat and mix in 1 tsp Kosher salt.
5. Lightly flour counter or other work surface, flour your hands and place dough on the floured surface. Gently knead the dough by folding it in half, pressing into it with the heel of your hands and turning it a quarter turn until it is no longer sticky (about 20-30 times). If your dough is too sticky, add more flour as necessary, 1 Tbsp at a time; the less flour you use and the less you knead the dough, the most pillowy your gnocchi will be.
6. Divide dough into three equal parts and then divide each part in three again, loosely rolling the nine dough pieces into balls.
7. On your floured surface, roll each ball of dough into a 1-inch thick log and cut each log crosswise into about 12 1-inch gnocchi pieces. To add a bit of flair, lightly roll press the tongs of a fork into each gnocchi and roll. Dough should make approximately 108 gnocchi.
8. Drop the gnocchi into boiling water and stir after a minute so they don't stick to the bottom. Boil gnocchi until they float to the top for a few seconds and are tender but firm, 8-10 mins.

Make the Sauce

1. While the gnocchi are cooking, melt butter over medium heat in a large skillet until foaming. When foam subsides, add the sage leaves and cook until sage is crisp and the butter is toasty and brown, about 5 minutes.
2. Drain the gnocchi without rinsing and add to the skillet with the browned butter and sage. Toss gnocchi to coat in sauce, add Parmigiano-Reggiano cheese and season to taste with salt and pepper.
3. Serve hot and garnish with more Parmigiano-Reggiano cheese, if desired.