In the fall, I often have two items lurking in my fridge.. leftover mashed potatoes, and leftover pumpkin puree. I've often thrown them out, much to my dismay. No more! After long research into "leftover mashed potato gnocchi," I think I've finally got it right. Many "leftover mash gnocchi" recipes don't take into account the extra liquid added (because really.. who doesn't put butter or cream in their mash) and you end up with a sticky, gummy mess. These were perfect—light, tender, but still toothsome, and is easy as pie to make. This recipe requires a little bit of "feeling it out," as the amount of flour will vary person to person, and a smooth mashed potato with as few clumps as possible will yield the best results. —Clair Gu
In a large bowl, combine the potatoes, pumpkin, and salt. With the back of a wooden spoon or rubber spatula, smash up any lumps you see. If you're feeling fancy, you cut run the mixture through a food mill to ensure no lumps remain.
Add in the egg yolk and stir vigorously to combine. The texture of the mixture will change slightly.. it should feel a little more elastic.
Add in the first half of your flour and stir. You should see your dough start to come together into a ball. Pour the other 1 cup flour onto your countertop and scrape your gnocchi ball into the middle. Knead gently (prepare yourself, you'll have doughy hands), adding flour as you go, until the dough is no longer super sticky and appears smooth. Let the dough rest for about 10-15 minutes.
After resting, cut the dough into 6 equal portions. Create a "log" shape with each piece. Dust with flour, then roll it with your palms into a cylinder about 1 inch in diameter. Cut the log into 1 inch pieces. To shape the gnocchi, push each piece gently down the backside of a fork, using your thumb. You should have a rough square with a little indent on the back and a ridge pattern on the front. Place the shaped gnocchi onto a baking sheet dusted with flour or semolina. Don't let them touch or they will stick to one another. Repeat for all dough logs.
Bring a large pot of water to an aggressive boil and add 2T salt. Drop the gnocchi in small groups into the water quickly (just don't let them touch until they hit the bottom of the pan). Boil for 2 minutes—the cooked gnocchi will bob up to the top when their done. Remove from the water with a scoop or slotted spoon and transfer to a plate. Top with your choice of topping or sauce. (NOTE: these are quite delicate so I would not recommend pouring them through a colander)
Optional: I topped this batch with brown sage butter, fried sage leaves, rehydrated and pan-roasted shiitake mushrooms, oven-roasted cherry tomatoes, a little parmesan broth, and grated parm reggiano.