
Overestimated your Thanksgiving crowd? This year, I'm easily repurposing my leftover mashed potatoes into another delicious potato classic—gnocchi.
In a large bowl, stir egg, flour, mashed potatoes, and salt with a rubber spatula, adding more flour 1/4 cup at a time if needed, until a dough comes together. Knead in bowl with your hands until smooth, about 2 minutes.
On a lightly floured surface, divide dough into 4 pieces. Using your hands, roll each piece to a long rope about 1/2" in diameter. Cut ropes into 1" pieces. Add more flour to surface as needed between ropes to prevent sticking. Arrange pieces on a baking sheet.
Using the back of a fork, roll each piece of dough along the tines to create ridges. Return to baking sheet. If dough is too sticky, sprinkle a small amount of flour over pieces before rolling on fork.
In a large pot of boiling salted water, cook gnocchi, stirring occasionally, until they float to the top, 1 to 2 minutes. Using a slotted spoon, transfer gnocchi to preferred sauce and toss to coat.
Make Ahead: Uncooked gnocchi can be cut 1 month ahead; transfer to a freezer-safe container and freeze.