Roast whole sweet potatoes at 425˚F on a baking sheet or tinfoil (to catch juices) until fork tender, about 20 minutes for small ones and 30-40 minutes for larger sweet potatoes.
Remove them from oven and let them cool enough to handle them, then peel and discard the sweet potato skins.
Mash the roasted sweet potatoes with a fork in a bowl. Add the flour and salt and stir with a fork until a dough starts to hold together. Knead dough together using clean hands just until it comes together into a smooth soft ball. Be careful not to over work the dough. The dough should be soft and pillowy, not firm or dense.
Divide dough into 6 equal portions. Working with one portion at a time, while covering the remaining dough with a kitchen towel, roll it out with your hands into a long log about 1/2" in diameter.
Cut the log into 1-1/2" length pieces. Lightly press each piece into the back of a fork or gnocchi board with your thumb and roll it down the tines or impressions to make indentations on one side and a slight concave dip on the other side. Repeat rolling cutting and shaping the remaining portions of dough.
At this point the gnocchi can be cooked right away or refrigerated in an airtight container for up to 2 days before cooking them. To freeze the gnocchi for longer storage first freeze them in a single layer on a baking sheet and then transfer them to a freezer bag and store in the freezer for up to 6 months. To cook frozen gnocchi add them directly to the boiling water, do not thaw them first.
To cook gnocchi, bring a large pot of water (at least 4 quarts) to a boil and add a handful of sea salt to the water.
Add fresh gnocchi to the boiling water, and cook at a rapid boil, stirring occasionally for about 5 minutes. Test one to make sure they are cooked through, with no raw flour taste, and are soft with a slight chew, not mushy. If they are not done, cook for a couple more minutes and test again. If cooking frozen gnocchi they may need a few more minutes to cook through.
Drain the gnocchi and coat or toss them in whatever sauce or sauté them in herbs and butter as you wish. Tip: save some of the pasta water to thin out the pasta sauce if needed.