Season beef cheeks with salt and pepper to taste. In a pot, heat oil over high heat and sear beef cheeks until golden brown on all sides, about one to two minutes per side. Remove from the pot and set aside.

Add onions to the pot and sauté until translucent, about three to four minutes. Add garlic and mushrooms, if using, and sauté three more minutes.

Add wine, stock, and sugar. Return beef cheeks to the pot and add more salt and pepper to taste.

Cook on low heat three and a half to four hours, turning meat occasionally, until beef cheeks are very tender. Shred with a fork.

In a small bowl, whisk together potato starch and water. Slowly mix into the meat and cook on high for three minutes, until thickened. Let meat cool, then freeze until ready to serve.

Preheat oven to 500 degrees Fahrenheit.

Wrap potatoes individually in aluminum foil. Place in a pan and bake one hour, or until soft. Let potatoes cool to room temperature, then peel (the peels should slide off easily using only your hands).

In a food processor fitted with the S blade, process potatoes until creamy.

Transfer to a bowl and add egg and potato starch. Knead mixture to form a dough, adding just a little more potato starch if needed. The dough should be moist, smooth, and silky, but not sticky.

Dust your work surface with potato starch. Roll dough into long ropes and cut into 1/4-inch pieces. If you like, press each gnocchi against the back of a fork to create ridges. (You can also leave them smooth.)

Line a pan with Gefen Parchment Paper and dust with potato starch. Place gnocchi in the pan in a single layer, not touching, and dust with more potato starch. Continue layering, making sure to dust the parchment paper and gnocchi with potato starch to prevent sticking. Freeze until ready to use.

Fill a six-quart pot with boiling, salted water. Tap off any excess potato starch from the gnocchi and carefully drop them in the pot, taking care not to overcrowd it.

Cook only 30 seconds, stirring once with a slotted spoon to prevent sticking. When the gnocchi rise to the surface, remove them immediately to a colander. (If you leave them in the pot for even a short time, they will become mushy.)

Rinse cooked gnocchi in freezing cold water for 30 seconds to prevent sticking. Drizzle with oil and toss to lightly coat. Mix with the shredded meat and serve.