Begin by placing the peeled and cubed sweet potatoes into a pot of boiling water. Cook them until they’re fork-tender, about 15 minutes. Drain well and return to the pot or a large bowl. Using a potato masher or fork, mash the sweet potatoes until smooth, ensuring there are no lumps. Let them cool slightly before moving on to keep that egg from scrambling in the dough.
Add the large egg, salt, and olive oil to the mashed sweet potatoes and mix well until fully incorporated. Gradually add the all-purpose flour, mixing gently until a soft dough forms. You want the dough to be pliable and just slightly sticky but not wet. If it’s too sticky, add a little more flour; if too dry, a splash of water or olive oil can help.
Divide the dough into four equal parts on a lightly floured surface. Roll each portion into long ropes about 3/4 inch thick. Using a knife or bench scraper, cut the ropes into 1-inch pieces. To create the traditional gnocchi shape, roll each piece down the back of a fork with your thumb to create ridges that help hold the sauce. This step is optional but highly recommended for texture.
Bring a large pot of salted water to a boil. Working in batches, gently drop the gnocchi into the boiling water. They’ll sink initially and then float to the surface when cooked, which typically takes 2-3 minutes. Use a slotted spoon to remove them and set aside on a plate.
In a large skillet, heat olive oil over medium heat. Add the minced garlic and sauté until fragrant and golden, about 1-2 minutes. Pour in the heavy cream, add nutmeg, and season with salt and pepper. Simmer gently for 3-5 minutes until the sauce thickens slightly.
Add the cooked gnocchi into the garlic cream sauce and toss gently to coat each piece evenly. Let it warm through for a minute or two. Remove from heat, garnish with fresh chopped parsley, and serve immediately.