Scrub potato and poke several times with a fork. Set directly on the rack of a 400-degree oven and bake until tender when poked, about 45 minutes, or zap until tender, about 10 minutes.
When cool enough to handle, press through a potato ricer onto a work surface. Let cool until no longer steaming.
Whisk:
Whisk together egg, nutmeg and 1/8 teaspoon salt. Pour egg mixture over riced potato and stir very gently with a fork, just to combine. Sprinkle on about 1/3 cup flour and continue to mix very gently and sparingly with fork or fingers until a soft dough forms.
Test:
Heat a large pot of salted water to a boil. Pinch off a bit of dough and drop it in. If it holds its shape, you're good to go. If it falls apart, add a little more flour to the dough.
Roll:
Divide dough in two. On a floured surface, roll each portion into a ½-inch thick rope. Slice crosswise into ½-inch segments.
Groove:
Flip a fork over. Roll each gnocchi down the back of the fork, pressing lightly, to imprint grooves. Not absolutely necessary, but what's the point of gnocchi if not looking adorable?
Boil:
Drop gnocchi into boiling water in 2 batches. Gnocchi will sink. Then, in about 1 minute, float. Wait 10 seconds. Scoop out gnocchi with a slotted spoon and drain on a clean kitchen towel.
Sizzle:
Heat butter over medium-high heat in a medium skillet. It will melt, then brown. Add sage, sizzle 1 minute. Add cooked gnocchi and toast, tossing gently until lightly browned, about 1 minute. Enjoy as an appetizer or scatter on an arugula salad as surprising croutons.
Leah Eskin is a Tribune Newspapers special contributor. Email her at leahreskin@aol.com.