Mix salt with flour. Combine slightly beaten egg with water (we like cream if we have it on hand, because the noodles are tenderer). Stir into flour mixture to make very hard dough. If it is too dry to handle, add water a few drops at a time, but keep it hard; don't let it get sticky. Knead dough on a lightly floured board until smooth (about 5 minutes). Cover and let stand for 20 to 30 minutes. Divide it into 2 or 3 parts, and roll each part paper thin. (This is the only difficult part to roll very hard dough very thin.) Roll each piece of dough jelly-roll fashion, or fold into several layers and slice evenly into narrow strips. Separate and straighten strips, and let dry thoroughly. Store in a jar in refrigerator until ready to use. When ready to cook, drop into rapidly boiling liquid and boil for 10 to 15 minutes, or until tender but not mushy.